SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
FORM 8-K/A
CURRENT REPORT
Pursuant to Section 13 or 15(d) of
The Securities Exchange Act of 1934
Date of Report: October 15, 2003
Colorado 000-29621 84-1384159 -------- --------- ---------- (State or other (Commission (IRS Employer jurisdiction of File Number) Identification No.) incorporation) |
Registrant's telephone number, including area code: (949) 330-8060
ITEM 1. CHANGES IN CONTROL OF REGISTRANT
The Plan and Agreement of Reorganization between Sun River Mining, Inc. and Xoptix, Inc. was completed on September 24, 2003. Pursuant to the Plan, the Company authorized the issuance of 110,530,000 (post reverse split) common shares.
ITEM 2. ACQUISITION OR DISPOSITION OF ASSETS
None
ITEM 3. BANKRUPTCY OR RECEIVERSHIP
None
ITEM 4. CHANGES IN REGISTRANT'S CERTIFYING ACCOUNTANT
None
ITEM 5. OTHER EVENTS AND REGULATION FD DISCLOSURE
The Company approved a reverse split on a one new share for twenty old shares basis, effective October 6, 2003.
The Company has also changed its name from Sun River Mining, Inc. to XSUNX, Inc. on September 30, 2003.
CERTAIN FACTORS AFFECTING FORWARD LOOKING STATEMENTS
In addition to statements of historical fact, this summary contains forward-looking statements. The presentation of future aspects of XsunX, Inc. ("XsunX, Inc." or the "Company") found in these statements is subject to a number of risks and uncertainties that could cause actual results to differ materially from those reflected in such statements. Some of these risks might include, but are not limited to, those discussed below. Readers are cautioned not to place undue reliance on these forward-looking statements, which reflect management's analysis only as of the date hereof. Without limiting the generality of the foregoing, words such as "may", "will", "expect", "believe", "anticipate", "intend", or "could" or the negative variations thereof or comparable terminology are intended to identify forward-looking statements. The Company undertakes no obligation to publicly revise these forward-looking statements to reflect events or circumstances that arise after the date hereof. Readers should carefully review the factors described in other documents the Company files from time to time with the Securities and Exchange Commission, including the Quarterly Reports on Form 10-QSB filed by the Company in 2003 and any Current Reports on Form 8-K filed by the Company.
NEW BUSINESS
On July 9, 2003, The Company entered into a Plan of Reorganization and Asset Purchase Agreement with Xoptix, Inc., a California corporation, to acquire the following three patents for Seventy Million (70,000,000) shares (post reverse split one for twenty): No. 6,180,871 for Transparent Solar Cell and Method of Fabrication (Device), granted on January 30, 2001; No. 6,320,117 for Transparent
Solar Cell and Method of Fabrication (Method of Fabrication), granted on November 20, 2001; and No. 6,509,204 for Transparent Solar Cell and Method of Fabrication (formed with a Schottky barrier diode and method of its manufacture), granted on January 21, 2003 (collectively, the "Patents"). The Company's new Business Plan is as contained herein. The Plan provided for the issuance of 70,000,000 shares for the Patents and 25,500,000 shares for services, and 230,000 shares to settle old bills (post reverse split one for twenty), in addition to the shares being sold hereunder. The transaction was completed on September 30, 2003.
HISTORY OF XOPTIX PATENTS
Xoptix, Inc. was founded in March 1999 to develop and exploit a new solar-based invention. Between March 1999 and the present, Xoptix focused primarily on protecting and validating its proprietary process for making a transparent window glazing which produces electricity.
Specifically, Xoptix has been granted three patents for a process for making solar electric glass. This yields a new class of thin film and glass products for use under the trade name "XsunX" (and which will be used hereafter to describe the technology). These films and glasses can replace a broad spectrum of common materials. Xoptix ceased business operations in 2001 due to lack of capital. Xoptix has sold its technologies and patent assets to the Company as part of a plan of liquidation of Xoptix and winding up of its corporate existence.
Products Strategy
XsunX has recently acquired the patents to technology for the manufacture of transparent solar cells. We anticipate that the primary product opportunity for this technology will be in establishing a viable process for the commercial manufacture of solar electric glass. This proprietary process will allow manufacturers to inexpensively apply a coating, film or glazing to glass, plastic and other materials, which is transparent and photovoltaic. Because XsunX glazing is transparent, the appearance of products manufactured using the XsunX process is not changed. When XsunX glazing is exposed to light, the light energy is converted into electrical energy for use as a power source.
Applications for Solar Electric Glass
While there are numerous ways to make solar cells, all of these methods result in a structure that is opaque. Thus, they are not appropriate for many applications. The need to place cells in areas where they do not obscure vision or building esthetics also limits deployment to areas of exceedingly small percentages of total available building surfaces. To date, this limiting factor has also presented ROI inefficiencies associated with costs per kW produced versus the Balance Of System (BOS) expenditures for mounting, wiring, power conditioning and grid connection.
On the other hand, XsunX solar electric glass technology provides an opportunity for up to 75% of a buildings exterior surface to produce electricity for use by the building. Efficiencies are gained in total kW produced and ROI on BOS expenditures. Management believes these unique properties provide major market potential in the following areas:
Architectural Glass - Large Buildings
XsunX glazing could be applied to the windows of large buildings, turning these structures into virtual power plants. Electrical power generated can be used to run building systems. In the future, the Company's management believes that a substantial portion of electrical power can be generated in dense urban areas with XsunX's solar electric glass. While the total amount spent annually on building products is over a trillion dollars, the total expenditure for XsunX solar electric glass could swell into the billions.
Architectural Glass - Homes
XsunX glazing could be applied to windows in homes to supply a portion of residential electrical power. The Company's management believes that these types of windows could eventually be supplied by companies such as Andersen Windows and could be sold directly at home improvement stores such as Home Depot. Film produced by companies such as 3M using the XsunX process could also be applied to new and existing windows.
Business Model
The Company's management believes that the primary target opportunity for XsunX's technology is makers and fabricators of glass. This is a very large industry, generating worldwide revenues in the hundreds of billions of dollars. The Company's strategy is to complete the development and commercialization of the XsunX process, and then enter into relationships with channel partners who will manufacture and distribute products made with XsunX solar electric glass technology. The Company's management believes that the most rapid and likely path to success involves licensing the XsunX process to companies with established manufacturing and distribution facilities.
The Company intends to promote the environmental and cost savings virtues of products manufactured with the XsunX process. By supplementing the marketing efforts of channel partners, the Company expects to accelerate the adoption of products that benefit from XsunX's solar electric glass technology.
Revenue Model
The Company's management believes that virtually all of the Company's revenues will come from the license of its proprietary XsunX solar electric glass technology to major manufacturers. Exclusive and non-exclusive know-how and intellectual property licenses will result in a substantial stream of royalty revenue for the Company. The Company's management estimates that manufactures of architectural glass will be willing to pay a royalty of at least 3% of gross sales for the non-exclusive right to manufacture XsunX flat glass. No contracts now exist.
Proprietary Technology
The best inventions are often simple in nature and come from looking at a problem from a different perspective. For the last 20 years, the solar industry has made tremendous strides in improving the efficiency of solar products. In fact, it is fair to say that nearly all of the work done to improve solar cells has been with the goal of improving their efficiency or cost. A small amount of work has been done to turn the existing solar technologies into products that could be integrated into larger portions of our environments. Ostensibly, the most benefits from solar technologies will come from the incorporation of vast amounts of solar cell technology into our environments.
Background of the Transparent Solar Cell Invention
Solar energy provides many advantages over traditional energy sources. For example, energy from the sun is virtually unlimited and easily accessible throughout the world. It does not require the extraction of a natural resource from the ground to obtain the energy and it can be converted to electricity in a manner that is not harmful to the environment. Solar energy is available whenever the sun is shining and can be collected and stored for use when no light source is available. Therefore, if it can be harnessed economically, it provides an environmentally friendly source of energy that does not deplete or destroy precious natural resources. This is in stark contrast to the use of fossil fuels that are of limited supply and which cause environmental damage with both their use and extraction processes. The use of fossil fuel also requires a constant source of raw materials that may be difficult obtain in many circumstances.
Many different applications benefit greatly from the use of solar energy. For example, buildings, with their broad surfaces that are exposed to the sun's energy for much of the day, can use that energy to provide some or all of their energy needs. Various solar cells have been developed using different fabrication techniques to take advantage of this energy source.
One type of solar cell is formed with crystalline silicon. For these solar cells, crystalline silicon is formed by melting silicon and drawing an ingot of crystalline silicon of the size desired. Alternatively, a ribbon of crystalline silicon can be pulled from molten silicon to form a crystalline silicon solar cell. A conductor is placed on either side of the crystalline silicon to form the solar cell. These processes use high temperatures and the solar cells are expensive to manufacture. Packaging is also difficult and expensive and creates a rigid structure. The manufacturing process limits their maximum size. It is difficult to slice the resulting crystalline silicon thin enough to provide a transparent or flexible solar cell. However, these structures are very efficient (relative to other types of presently available commercial solar cells). As such, crystalline solar cells are used primarily for applications where efficiency is more important than cost and where the structures do not need to be flexible. For example, these are commonly used on satellites.
Another type of solar cell is formed with polycrystalline silicon. These may be formed as thin layers on wafers and can thus be made thinner than crystalline silicon solar cells. As is well known in the art, heating amorphous silicon can form polycrystalline silicon. Typically, amorphous silicon begins to crystallize at temperatures greater than about 1400(Degree)C. Because of these high temperatures, known processes can only use substrates with high melting points. These processes are not appropriate for substrates made of plastics or other materials that melt at lower temperatures. In the manufacture of flat panel displays, it is known to use lasers to form polycrystalline silicon thin film transistors (TFTs). Such use has not included the formation of P-N junctions or solar cells that presents its own set of challenges. Moreover, these manufacturing processes generally formed single transistors and were not used to form large sheets or areas of polycrystalline silicon. Further, lasers have been used in the manufacture of solar cells, but only as a tool to mechanically form (slice, pattern, etch, etc.) the solar cells.
Another type of solar cell has been formed using doped layers of amorphous silicon. These are not subject to some of the problems inherent in the previously described crystalline silicon or polycrystalline solar cells. First,
amorphous silicon can be formed using low temperature processes. Thus, it can be formed on plastic and other flexible substrates. They can also be formed over large surfaces. Second, the processing techniques are less expensive. Nevertheless, amorphous solar cells introduce other significant limitations not found in crystalline silicon or polycrystalline silicon solar cells. For example, hydrogen is generally added during the manufacturing to increase the efficiency of the cell. Amorphous silicon solar cells tend however to lose this hydrogen over time, causing reduced efficiency and reduced usable life. Moreover, amorphous silicon solar cells are not transparent. Thus, they are not appropriate for many applications. For example, buildings with solar cells can be unsightly, and the solar panels may block the view of the outdoors or access to outside light indoors. Also, portable electronics often place a premium on size and surface area. Some devices have displays that cover most -- if not all -- of the exposed surface of the device. Therefore, it is often undesirable or impossible to mount a traditional amorphous silicon solar cell on the device.
Attempts have been made to solve this transparency problem by making transparent panels from existing solar cell processes. One method has been to take advantage of the "window shade effect" whereby solar cells are formed on a transparent substrate with gaps between adjacent solar cells. This allows some light to pass through to create a transparent effect. The larger the gaps, the more transparency the device has. A disadvantage of this technique is that much of the space is unused; therefore the efficiency of the device is less than it would be if all of the surface areas were used for solar cells. Of course, devices of this type also suffer from the problems inherent to the type of cell used. For example, if based on amorphous silicon, these devices suffer from the hydrogen loss exhibited in other amorphous silicon devices.
Other work has been done at making transparent solar cells using materials other than silicon (for example, cadmium telluride (CdTe)). These cells suffer from the challenges inherit to using materials other than silicon.
The XsunX Process
The XsunX technique for making transparent solar cells leverages two distinctly different technologies -- amorphous solar cell process and flat panel display process -- that have not previously been linked. By adding known processing techniques to those commonly used in the solar industry, XsunX has been able to create and protect a structure that is both transparent and photovoltaic.
The XsunX Process combines the following advantages:
o It is transparent and therefore can be used in places inapplicable to existing solar cells.
o It is cost effective because it uses thin film amorphous silicon.
o It may be readily manufactured because the methods for manufacture uses commercially available chemical vapor deposition and laser annealing equipment.
o It can be used on a wide variety of substrates including low temperature substrates.
The Method of Fabrication
It is anticipated that the XsunX Process will provide a method and structure that will form a substantially transparent solar cell. The solar cell is anticipated to be thin, flexible, and easy to make and use with conventional semiconductor processes. The solar cell is also anticipated to operate effectively as an optical filter.
In a specific embodiment, the XsunX Process includes a method of forming a solar cell. The method includes steps of providing a substrate, such as glass, plastic, Mylar and other substrates, including those with low melting points. The method also includes forming a first conductive layer overlying the substrate. The method also includes forming a first amorphous silicon layer of a first dopant type overlying the first conductive layer. A step of annealing the first amorphous silicon layer is included. The method also forms a second amorphous silicon layer of a second dopant type, and also anneals the second amorphous silicon layer. A second conductive layer is formed overlying the second amorphous silicon layer. A combination of these steps forms a transparent solar cell structure.
In an alternative aspect, the XsunX Process provides a solar cell structure that is transparent. The structure includes a transparent substrate, which can be selected from glass, crystal, plastic, Mylar, and other substrates, including those that have low melting points. A conductive layer is formed overlying the transparent substrate. A first polycrystalline silicon layer from a first amorphous silicon layer of a first dopant type is formed overlying the first conductive layer. The structure also includes a second polycrystalline silicon layer from a second amorphous silicon layer of a second dopant type overlying the first polycrystalline silicon layer, and a second conductive layer overlying the second polycrystalline silicon layer. The combination of these layers forms a transparent structure.
In a further aspect, the XsunX Process provides a method for fabricating a structure comprising a transparent solar cell structure. The method includes
forming a first conductive layer overlying a transparent substrate, and forming a first amorphous silicon layer overlying the first conductive layer. The method also includes converting the first amorphous silicon layer into a first polycrystalline silicon, and forming a second amorphous silicon layer overlying the first amorphous silicon layer. A step of converting the second amorphous silicon layer into a second polycrystalline silicon is included. The method also includes forming a second conductive layer overlying the second amorphous silicon layer. The combination of these steps forms a transparent solar cell structure overlying the substrate.
In still a further aspect, the XsunX Process provides a solar cell comprising a substrate with a melting temperature of less than 450(Degree) C, a first conductive layer overlying the substrate, a first polycrystalline film overlying the first conductive layer, a second polycrystalline film overlying the first polycrystalline film, and a second conductive layer overlying the second polycrystalline film.
Advantages of the XsunX Process
The XsunX Process will achieve numerous advantages over conventional techniques for forming solar cells. For example, the present XsunX method uses conventional equipment and processes from semiconductor operations to manufacture the solar cells. In one aspect of the XsunX Process, an Excimer laser is used to anneal the amorphous silicon layers. Use of this, or a similar laser, allows the forming of polycrystalline silicon without exposing the substrate to high temperature that will distort or destroy it. Therefore, low melting point materials such as plastic may be used. The XsunX solar cells can be transparent, which makes them desirable for placing over glass and other see through structures. In other aspects, the invention is expected to be easy to implement and control. The present cell structure is extremely thin and efficient and can be implemented on a variety of applications.
For example, it can be formed on a flexible substrate and substantially maintain the flexibility of the substrate. Depending upon the embodiment, one or more of these advantages may exist. Other advantages may also exist depending upon the embodiment. A transparent solar cell produced with the XsunX Process will also have a lower efficiency than a standard solar cell.
Conversely, the ability to incorporated larger amounts of XsunX cells on to a structure provides for significant opportunities to produce greater amounts of usable energy. Conventional PV technology installation is typically limited to very small percentages of a buildings usable surface. XsunX PV technology may see building surface integration of as much as 75% in commercial applications providing many times the kW production associated with smaller installations of conventional opaque PV cells.
The Company's management has a high level of confidence that the Company can successfully complete the commercial process development because the XsunX process is either:
o A mature process of making amorphous silicon solar cells plus one mature step from the process of making flat panel displays, or
o A mature process of making flat panel displays plus the mature step of sandwiching it with ITO on a substrate
The XsunX process for producing a transparent solar cell uses standard (commercially available) equipment, inexpensive materials and many well-understood processes.
The Company's management estimates that a transparent solar cell produced with the XsunX process will have a lower efficiency than a standard solar cell for the following reasons:
Poly-crystalline cells are more efficient than amorphous cells
At least 25% of the photons will be annihilated within 1000 Angstroms
ND1 Solar Filter will be at least 4000 Angstroms - conservative number is 50% for ND1 filter
XsunX transparent solar cells will have a very wide dynamic range of efficiency depending on the application and the optical filter characteristics.
Future Products
XsunX intends to extend its brand name and capitalize on its channel partner relationships by developing additional building integrated photovoltaic products in the future. The Company realizes that the cost of product development is becoming increasingly more expensive. To assure the best possible new product decisions are made, the Company has implemented the following criteria for evaluating and selecting new products:
o Product opportunity is presented by established license partner with provisions for adequate marketing support
o Product assists users by reducing time, effort or expense
o Product can be implemented using the Company's existing channels of distribution.
o Product potential is investigated, and market research is undertaken to estimate the numbers of potential users that can be reached.
o Product complies with any and all new laws or government programs or regulations bearing impact within the next five years.
o New products will be added as new opportunities are identified.
o The Company will use outside material providers when they have the resources necessary to expedite the development of an XsunX product. They will be selected based upon their expertise, active participation, reputation and success in their field. When beneficial, the Company seeks to blend the offerings of several providers to create an optimum hybrid product yielding the most benefits to its customers.
o A product must be improved every 12 months in order to maintain its competitive position, market value and price point. The Company must maintain its ability to provide useful products as the environment, its customers' needs, and its capabilities change.
Market Analysis
XsunX's transparent photovoltaic glazing for glass, plastic and other materials promises to be a break-through technological innovation that will make solar energy economically feasible and may cause the solar energy market to explode.
The Company's technology can be applied to the already quite large and established glass industries. That is, transparent glazing will enable solar energy-production to enter mainstream markets because it can readily become integral to the designs of buildings. Builders and manufacturers already use glass, plastic and other materials, so they will be especially attracted to the economic benefits of using the same materials that also produce electrical energy.
In the long view, solar energy production is intrinsically attractive, not only environmentally but also economically. Sunlight is readily, regularly, and widely available; it is renewable; and it is easily accessible without the massive expense of mining, drilling, or constructing huge dams or other facilities. Tapping the sun directly, rather than through the solar energy stored in fossil fuels, wood, or ethanol, makes too much economic sense not to be inevitable.
A major factor in the restricted use of solar energy has been the technological limitations of large-scale solar energy production, particularly active production of electricity rather than passive collection of heat. For buildings, residential and nonresidential, photovoltaic technology has shown it can significantly reduce the need for electricity generated through other means, but the additional cost of purchasing and installing photovoltaic systems has been prohibitive, especially compared to the cost of electricity through other means.
XsunX's patented technology may make solar energy production economically and technologically feasible for the building industry because it allows glass, plastic and other materials to produce electricity while remaining transparent and thus functional as a window or display surface. The architectural limiting aspects of current photovoltaic technologies may soon disappear as XsunX glazing turns commercial and residential structures, and their vast areas of modern architectural glass, into virtual power plants.
The Company's management believes that the primary target markets for XsunX's technology are makers and fabricators of glass. This is a very large industry, generating worldwide revenues in the hundreds of billions of dollars. It breaks down into two areas relevant to XsunX's technology:
o Nonresidential construction, primarily architectural glass for large edifices, such as office buildings, hospitals, schools, retail buildings, and industrial buildings.
o Residential construction, primarily doors and windows for homes.
The construction industries fluctuate in direct relationship to the growth of the overall economy. They are, nevertheless, very large, stable markets over the long term. In addition, the flat glass industry for the construction industry is geared for technological innovations, including especially those that help control sunlight for greater energy efficiency.
Other factors indicating favorable market conditions for XsunX include:
o A boom market for nonresidential and residential construction, spurred by strong low interest rates.
o A growing concern in nonresidential construction with energy efficient buildings, possibly spurred by recent dramatic hikes in energy costs, especially oil.
As an innovative, patent technology, the competition for XsunX's transparent solar cell technology is primarily current modes of producing and glazing glass and plastic. These include various technologies to control sunlight and increase heating and cooling efficiency in buildings and cars and advances in battery-powered technology for electronics.
With its breakthrough process in the solar production of electricity, XsunX will have clear advantages marketing its technology. XsunX transparent solar cell technology will enable manufacturers to make buildings more efficient and ultimately more cost-effective, while also reducing dependency on fossil fuels and other technologies that harm the environment.
The Underdeveloped Market for Photovoltaic Products
Electricity produced by photovoltaic products is growing rapidly, but remains a very small percentage of overall U.S. energy production, and a very small percentage of its potential. Despite the attraction of clean, renewable, safe energy production, solar electricity fails to compete with other means of producing electricity in part because of technological limitations, which often make solar energy economically unfeasible. This is especially true for large-scale energy production. XsunX's transparent solar cell technology opens new markets for solar energy applications in construction and other industries as it makes the option of solar energy economically feasible.
Marketing Plan
XsunX's marketing strategy is to create a favorable environment to license its solar electric glass technology. The Company intends to enhance, promote and support the fact that products produced with the XsunX process provide users with a best of class technology that spans and interconnects glass, optical film and energy markets market's to provide substantial economic and environmental benefits.
Product and Service Differentiation
The differentiating attributes of products produced with the XsunX process include:
o Energy from a renewable source - solar
o Transparent nature eliminates inhibiting architectural applications
o May be applied to glass or flexible substrates
o Provides distributors with valuable bundling opportunities
o May be applied with low temperature - allows for a variety of
substrates
o High level of reliability
o Reasonable cost
Value Proposition
The Company's value proposition is simple: XsunX technology fills the voids in today's solar technologies allowing the production of solar electricity to become part of our environment as a natural use of space and makes more sense out of how we control our environments and draw the most from them.
Positioning
XsunX's unique value proposition can be exploited to arrive at a winning position in the minds of its customers. The Company must be positioned as the only source of commercially viable, solar electric glass -- providing users with substantial economic and environmental benefits.
Advertising and Promotion
XsunX recognizes that a key to success will be to undertake focused advertising and promotion efforts aimed at developing product awareness within the glass manufactures, fabricators, optical film, and building industries. This campaign will be performed aggressively and on a scale necessary to meet license sales goals. To accomplish its licensing goals, the Company requires a capable advertising agency and public relations firm. Subject to the recommendation of a marketing director, an agency will be selected and, with their assistance, a comprehensive advertising and promotion plan will be drafted.
Advertising and Promotion Objectives
XsunX's overall advertising and promotion objectives are to:
o Position XsunX as a leader building integrated photovoltaic markets.
o Increase Company awareness and brand name recognition among prospective customers.
o Generate qualified sales leads for the Company's field sales organization.
o Develop, through market research, significant information to create immediate and long-term marketing plans.
o Create product and service advertising programs supporting the Company's value proposition.
o Coordinate sales literature, demonstration materials, telemarketing programs, and direct response promotions in order to present a unified marketing approach.
Media Objectives
XsunX's media objectives are to:
o Increase awareness of the Company in the glass and building industries.
o Establish an image of XsunX as an organization that is professional, completely reliable, and highly positioned in the market.
o Maximize efficiency in selection and scheduling of published ads in publications to cover all targeted markets.
Print Media Strategy
XsunX's print media strategy is to:
o Select primary business publications with high specific market penetration.
o Schedule adequate frequency of ads to impact market with corporate image and product messages.
o Where possible, position advertising in or near industry articles, product reviews, center spread or appropriate editorials.
o Utilize U.S. editions of consumer, trade, or specialty publications.
o Take advantage of special high-interest issues of major publications when possible.
o Maximize ad life with monthly and weekly publications.
The Company will develop an advertising campaign built around a solutions oriented ad campaign message, beginning with a "breakthrough technology" statement and supporting it with ads that reinforce this message. Additionally, the Company will schedule its advertising campaign to develop a consistent reach and frequency throughout the year.
Advertising Campaign
An effective way to reach the Company's potential customers is to develop a targeted advertising campaign promoting XsunX Technology. To establish and maintain the Company's image, the delivery and tone of its statements will be informative. Ads will convey the look and feel of a successful company. Ideally, after becoming familiar with the Company's products, prospective customers will call for more information or visit the Company's Web site.
Trade Shows
XsunX will participate in industry trade shows, where the Company is likely to meet new alliance partners and licensing customers. The number of trade shows attended will be increased each year. These shows will be attended independently and with companies with which XsunX has joint marketing/sales or OEM agreements.
In deciding on the XsunX plan for trade shows, the following factors have been taken into consideration:
o Target audience of the show - will this get the message to the Company's target market
o Geographic location - a good mix of shows around the country.
o Time frame - preferably no more than one show a month.
o Past experience, if any with the show.
o Participation in someone else's booth.
Reports and papers will be published for trade journals supporting trade shows and technical conferences.
Sales Support Collateral Materials
XsunX plans to develop a variety of collateral materials to support its sales efforts. These items are intended to sell the Company's products and services.
Plan of Operations
XsunX anticipates the 12-month capital operational requirements of the company to be $2,250,000 dollars. We are preparing to raise this amount through the placement of equity capital in the form of one or more private offering's of XsunX's shares of common stock to accredited investors. These net proceeds from the offering of the Common Stock are estimated to be utilized as follows: (i)
approximately $718,000 will be used to pay costs associated with research and preparation of a plan of operations by the company's technical advisory board for the development of XsunX Process and the completion of development of a production model for the XsunX Process, (ii) approximately $623,000 will be used to pay salaries and general administrative costs and for intellectual property protection, (iii) approximately $87,000 will be used to pay for testing and development equipment, (iv) approximately $301,000 will be used to pay for market development research, general competitive research and publicity costs, and (v) approximately $521,000 will be used for general working capital.
The Company may change any or all of the budget categories in the execution of its business attempts. None of the items is to be considered fixed or unchangeable.
The Company will need substantial additional capital to support its budget. The Company has no revenues. The Company has no committed source for any funds as of date here. No representation is made that any funds will be available when needed. In the event funds cannot be raised when needed, the Company may not be able to carry out its business plan, may never achieve sales or royalty income, and could fail in business as a result of these uncertainties.
Backlog of Orders. There are currently no orders for sales at this time.
Government Contracts. None at this time.
Competitive Conditions. Currently, the management is not aware of other products similar to those of the company on the market. However, larger existing firms are developing competitive products and may have extensive capital for development work.
Company Sponsored Research and Development. No significant research is being conducted. However, with proceeds of future capital raising, the Company plans to engage in significant development of its technology. (See "Use of Proceeds.")
The operations of the Company are subject to local, state and federal laws and regulations governing environmental quality and pollution control. To date, compliance with these regulations by the Company has had no material effect on the Company's operations, capital, earnings, or competitive position, and the cost of such compliance has not been material. The Company is unable to assess or predict at this time what effect additional regulations or legislation could have on its activities.
Number of Persons Employed. As of October 1, 2003, the Company has one full-time Employee. Other Executive Officers and Directors work on an as needed basis.
ITEM 6. RESIGNATIONS AND APPOINTMENTS OF REGISTRANT'S OFFICERS AND DIRECTORS
Tom Anderson resigned as President and CEO effective September 30, 2003.
Tom Djokovich was appointed President and CEO of the Company effective September
30, 2003. Randy McCall and Steve Weathers will resign from the Board of
Directors effective ten days after mailing of Notice to Shareholders pursuant to
Section 14f of the Securities Exchange Act. Brian Altounian has been appointed
as Secretary and as a director effective immediately.
Tom Djokovich has been appointed as a director effective ten days after mailing of Notice to Shareholders pursuant to Section 14f of the Securities Exchange Act.
BRIAN ALTOUNIAN, Chairman of the Board, Secretary and Director
Mr. Altounian has over 16 years of experience in the area of finance, administration and operations. Most recently, he served as Executive Vice President of Plyent, Inc., a provider of a proprietary software solution that allows dynamic wireless Web access by Web enabled wireless thin clients, such as cell phones and personal digital assistants (PDAs). Mr. Altounian previously served as the Vice President of Finance for Lynch Entertainment, a producer of family television series' for the Nickelodeon and Disney Channels. While at Lynch, he established subsidiary corporations, purchased and oversaw the construction of a state-of-the-art television studio facility, and built the infrastructure of the company. Prior to joining Lynch Entertainment, Mr. Altounian held key management positions at numerous entertainment companies including Director of Finance and Administration at Time Warner Interactive; Finance Manager for National Geographic Television; and Manager of Business Services for WQED, the nation's first community-owned public television station. He also founded his own consulting company, BKA Enterprises, a firm that supported and advised entertainment and multimedia companies in the areas of financial and business management. Mr. Altounian holds an undergraduate degree from UCLA and an MBA from Pepperdine University.
TOM DJOKOVICH, President and Chief Executive Officer as of September 30, 2003; Board of Director Nominee:
Mr. Djokovich was the founder and served from 1995 to 2002 as the Chief Executive Officer of Accesspoint Corporation, a vertically integrated provider of electronic transaction processing and e-business solutions for merchants. Under Mr. Djokovich's guidance, Accesspoint became a member of the Visa/MasterCard association, the national check processing association NACHA, and developed one of the payment industry's most diverse set of network based transaction processing, business management and CRM systems for both Internet and conventional points of sale. During his tenure, Accesspoint became an early adopter of WAP based e-commerce capabilities and the industry's first certified Level 1 Internet payment processing engine. In his last year as executive manager, Accesspoint grew its processing revenues by over 800% and overall revenues by nearly 300%. Prior to Accesspoint, Mr. Djokovich founded TMD Construction and Development in 1979. TMD provided effective cost management of multimillion-dollar projects incorporating at times hundreds of employees, subcontractors and international material acquisitions for commercial, industrial and custom residential construction services as a licensed building firm in California. In 1995 Mr. Djokovich developed an early Internet based business-to-business ordering system for the construction industry. Mr. Djokovich also currently serves as a Director for Roaming Messenger, Inc., a publicly reporting company that provides a breakthrough software solution for delivering real-time actionable information for Homeland Security, emergency response, military and enterprise applications.
ITEM 7. FINANCIAL STATEMENTS & EXHIBITS
Financial Statements - None.
Exhibits:
3.3 Amendment to Articles of Incorporation
10.1 Plan and Agreement of Reorganization
10.2 Abstract of Patent - 6,320,117 10.3 Abstract of Patent - 6,509,204 10.4 Abstract of Patent - 6,180,871 |
10.5 Assignment of Patent - 6,180,871
10.6 Assignment of Patent - 6,320,117
10.7 Assignment of Patent - 6,509,204
ITEM 8. CHANGE IN FISCAL YEAR
None
ITEM 9. REGULATION FD DISCLOSURE
THIS EXECUTIVE SUMMARY DOES NOT ITSELF CONSTITUTE A SECURITIES OR AN OFFER TO BUY OR SELL SECURITIES. THE SECURITIES, IF ANY, DISCUSSED OR REFERENCED HEREIN ARE NOT BEING OFFERED FOR SALE IN ANY MANNER HEREBY AND HAVE NOT BEEN APPROVED OR DISAPPROVED BY THE SECURITIES AND EXCHANGE COMMISSION OR ANY STATE SECURITIES COMMISSION NOR HAS THE SECURITIES AND EXCHANGE COMMISSION OR ANY STATE SECURITIES COMMISSION PASSED UPON ANY OF THE STATEMENTS OR MATERIAL CONTAINED IN THIS EXECUTIVE SUMMARY. THIS EXECUTIVE SUMMARY IS NOT PART OF ANY CONFIDENTIAL OFFERING MEMORANDUM OR PROSPECTUS.
Executive Summary
XsunX, Inc. (XsunX) has acquired a breakthrough-patented technology to produce solar electric glass. This proprietary process is intended to allow manufacturers to apply a transparent and photovoltaic glazing to glass and other transparent substrates. When XsunX glazing is exposed to light, the light energy is converted into electrical energy for use as a power source.
XsunX believes that its patented solar electric glass technology has a number of major market opportunities in the multi-billion dollar worldwide architectural glass markets. The company intends to take advantage of this commercial opportunity to provide governments, developers, businesses and architects with a commercially viable method for converting today's large areas of architectural glass into virtual power plants.
The Solar Electric Glass Opportunity
XsunX's transparent photovoltaic glazing for glass and other materials may provide a break-through technological innovation that will make solar energy economically feasible and may cause the solar energy market to explode.
The Company's technology can be applied to the already quite large and established glass and building industries. That is, transparent glazing will enable solar energy-production to enter mainstream markets because it can readily become integral to the designs of buildings. Builders and manufacturers of building products already use glass, plastic and other materials, so they will be especially attracted to the economic and marketing benefits of using the same materials to produce electrical energy while continuing to function as window or display surfaces. XsunX intends to be a technology leader in the field of building integrated photovoltaics (BIPV).
Advantages Offered by Transparent Solar Cell Technology
With its unique patented solar glazing technology to produce electricity from sunlight, XsunX believes it has no direct competition. The Company's challenge in entering its target market segments is to demonstrate the advantages of its transparent solar cell technology over current designs.
In the glass industry, the advantages of XsunX's transparent solar cell technology are not only quite clear, but solar glazing technology is much anticipated. This is especially true in the market for architectural glass, which is why architectural glass is XsunX's best initial market.
Applications for Solar Electric Glass
While there are numerous ways to make solar cells, all of these other methods result in a structure that is opaque. Thus, they are not appropriate for many applications. The need to place these other cells in areas where they do not obscure vision or building esthetics also limits installation of these other methods to areas of exceedingly small percentages of total available building surfaces. To date, this limiting factor has also presented Return On Investment (ROI) inefficiencies associated with costs per kW produced versus the Balance Of System (BOS) expenditures for mounting, wiring, power conditioning and grid connection.
On the other hand, XsunX solar electric glass technology provides an opportunity for up to 75% of a buildings exterior surface to produce electricity for use by the building. Efficiencies are gained in an increase of total kW's produced averaged across BOS expenditures providing the opportunity for a more rapid ROI. Management believes these unique properties provide major market potential in the following areas:
Nonresidential construction - primarily architectural glass for large edifices, such as office buildings, hospitals, schools, retail buildings, and industrial buildings.
Residential construction - primarily doors and windows for homes.
Business Model
The Company's management believes that the primary target opportunity for XsunX's technology is makers and fabricators of glass. This is a very large industry, generating worldwide revenues in the hundreds of billions of dollars. The Company's strategy is to complete the development and commercialization of the XsunX process, and then enter into licensing relationships with channel partners who will manufacture and distribute products made with XsunX solar electric glass technology.
Revenue Model
The Company's management believes that virtually all of the Company's revenues will come from the license of its proprietary XsunX solar electric glass technology to major manufacturers. The Company's management estimates that manufactures of architectural glass will be willing to pay a royalty of at least 3% of gross sales for the non-exclusive right to use the XsunX process.
The XsunX Process
The Company's technique for making solar electric glass leverages two distinctly different technologies -- amorphous solar cell process and flat panel display process -- that have not previously been linked. By adding known processing techniques to those commonly used in the solar industry, the Company has been able to create and protect a structure that is both transparent and photovoltaic. The Company believes that its XsunX Process combines the following advantages:
It is transparent and therefore can be used in places inapplicable to existing solar cells.
It is cost effective because it uses thin film amorphous silicon.
It may be readily manufactured because the method for manufacture uses commercially available CVD and laser annealing equipment.
It can be used on a wide variety of substrates including low temperature substrates.
In addition to the production of electricity the solar cell is also anticipated to operate effectively as an optical filter.
The following chart offers key comparative analysis:
Conventional PV Solar Cells XsunX Solar Electric Glazing
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Current costs of approximately $450-500/sq. meter for The anticipated method for the manufacture of XsunX
crystalline-silicon PV modules. Production process is not glazing employs the use of mass production CVD and
conducive to high volume production rates. Newer thin film annealing systems readily in use today. These methods
PV systems are anticipated to reach costs of $75-100/sq. and systems are intended to establish production line
meter and employ production methods that provide somewhat economy's that may result in per meter production costs
higher production volumes then crystalline-silicon. similar to those found for current high performance
optical films and glass coatings.
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Current technology requires area related balance of system XsunX glazing is an integral part of the building glass
installation costs of $135/sq. meter. This includes the cost facade, therefore it is anticipated that installation
of mounting, land or building space and wiring. costs will be incidental aside from the expense
associated with wiring.
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Power conditioning, battery storage and power inverters Similar costs associated with XsunX technology.
average $200 per peak kW.
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Building area available for solar module installation Amount of potential building area available for XsunX
typically reserved to roof areas and certain facades. Sample solar electric glass installation for the same 20 story
roof panel system size at between 300-750/sq. meters for a office building at 75% of available exterior glass area
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20 story building 61 meters tall and 46 meters wide. is estimated to be 8,400/sq. meters
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Amount of the sun's peak energy converted to electrical Amount of the sun's peak energy converted to electrical
power by PV cells averages between 10-15% /sq. meter. power by XsunX glazing is estimated to average 1.5-2.5%
/sq. meter depending on cell filtering specifications.
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Amount of peak power produced by 500/sq. meters of solar Amount of peak power produced by 8,400/sq. meters of
panels mounted to the roof of the sample 20 story building XsunX glazing applied to the glass facade of the sample
operating at 14% efficiency, 70 kW. building operating at 2% efficiency, 168 kW.
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Other efficiencies include the potential for government XsunX glazing may also operate as an optical filter
sponsored credits, depreciation credits, net metering and eliminating the need for the additional use of costly
re-sale of surplus power, property improvement valuations in UV filter films and glazings applied to modern
some areas equal to 20 times the annual savings of power architectural glass facades. This dual benefit feature
produced. (XsunX glazing also enjoys these same benefits.) provides construction cost credits that may be factored
in to reduce XsunX costs.
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The Market
According to the U.S. DOE, Photovoltaics is a billion dollar a year industry and is expected to grow at a rate in excess of 15-20% per year over the next several decades. In the last thirty years, the cost per watt produced by solar electric technology has dropped by over 90% and efficiency rates have steadily grown. Today, the amortized costs over a fifteen-year period of new thin film solar cells are estimated to achieve cost rates equal to $0.08-0.11/kWh. Over this same period, the cost per watt for fossil fuel based electrical power may continue to rise and become ever increasingly susceptible to political and domestic uncertainty.
The market for Photovoltaics will continue to grow into the billions. The market for architectural glass, optical films and glazings are collectively in the billions and the markets for energy are infinitely larger. XsunX solar electric glazing spans and works to interconnect these markets opening innovative new product and revenue opportunities for these industries and XsunX.
Value Proposition
The XsunX value proposition is simple: The source of commercially viable, solar electric glass providing users with substantial economic and environmental benefits.
XsunX technology fills the voids in today's solar technologies allowing the production of solar electricity to become part of our environment as a natural use of space and makes more sense out of how we control our environments and draw the most from them.
Financial Plan
XsunX is raising equity capital through a private offering of the Company's shares of common stock to accredited investors (the "Offering"). The proceeds of the Offering will be used to complete the commercial development of the XsunX technology, establish infrastructure and undertake preliminary marketing and selling efforts. The Offering is being conducted under an exemption from registration set forth in Rule 506 of Regulation D for federal securities law purposes. The Offering is described in the Company's Private Placement Memorandum.
Additional documents available: The purpose of this summary is to provide an outline of the XsunX opportunity. As this is a new application environment and solution, outside of conventional experience and application, more detailed information may be necessary for a full review and understanding of the opportunity. The following are available for review:
o Confidential Offering Memorandum]
o The company web site at www.xsunx.com
Safe Harbor Statement: Matters discussed in the foregoing executive summary contain forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. When used in summary, the words "anticipate," "believe," "estimate," "may," "intend," "expect", "potential" and similar expressions identify such forward-looking statements. Actual results, performance or achievements could differ materially from those contemplated, expressed or implied by the forward-looking statements contained herein. These forward-looking statements are based largely on the expectations of the Company and are subject to a number of risks and uncertainties. These include, but are not limited to, risks and uncertainties associated with: the impact of economic, competitive and other factors affecting the Company and its operations, markets, product, and distributor performance, the impact on the national and local economies resulting from terrorist actions, and U.S. actions subsequently; and other factors detailed in reports filed by the Company. Readers should carefully review the factors described in other documents the Company files from time to
time with the Securities and Exchange Commission, including the Quarterly Reports on Form 10-QSB filed by the Company in 2003 and any Current Reports on Form 8-K filed by the Company. Statistics and comparative analysis charts contained in this summary express certain industry estimates and statements and are subject to the diversity of manufacturing, sales and physical aspects of solar module production and installation. Readers are cautioned not to place undue reliance on these forward-looking statements, which reflect management's analysis only as of the date hereof. This document contains confidential and proprietary information belonging exclusively to XsunX, Inc. and may not be duplicated.
ITEM 10. AMENDMENTS TO THE REGISTRANT'S CODE OF ETHICS, OR WAIVER OF A PROVI- SION OF THE CODE OF ETHICS
None.
ITEM 11. TEMPORARY SUSPENSION OF TRADING UNDER REGISTRANT'S EMPLOYEE BENEFIT PLANS
None.
ITEM 12. RESULTS OF OPERATIONS AND FINANCIAL CONDITIONS
None.
SIGNATURES
Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized.
Date: October 15, 2003
XSUNX, INC.
By: /s/ Tom Djokovich
--------------------------------
Tom Djokovich, CEO/President
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Plan of Reorganization and Asset Purchase Agreement
This Plan of Reorganization and Asset Purchase Agreement (the "Agreement") is made and entered into as of the 9th day of July 2003 by and between Xoptix, Inc., a California corporation ("Seller"), and Sun River Mining, Inc., a Colorado corporation ("Buyer"), with respect to the following facts:
R E C I T A L S
A. Seller is the owner of the following three patents: No. 6,180,871 for Transparent Solar Cell and Method of Fabrica- tion Device), granted on January 30, 2001; No. 6,320,117 for Transparent Solar Cell and Method of Fabrication (Method of Fabrication), granted on November 20, 2001; and No. 6,509,204 for Transparent Solar Cell and Method of Fabrication (formed with a Schottky barrier diode and method of its manufacture), granted on January 21, 2003 (collectively, the "Patents").
B. Buyer is a Colorado corporation that desires to purchase the Patents on the terms and subject to the conditions set forth in this Agreement.
C. The shareholders of Seller are currently voting on and will approve the sale of the Patents to Buyer pursuant to the Solicitation of Consents dated July 9, 2003. The Board of Directors of Seller has approved the proposed sale of the Patents to Buyer.
D. Immediately after the closing of the sale of the Patents, Seller will convey executed and notarized assignments of the Patents, copies of which are attached to this Agreement as Exhibit A, to Buyer to be recorded with the United States Patent and Trademark Office and Buyer will issue to Seller stock certificates representing a total of Seventy Million (70,000,000) shares of Buyer's common stock which Buyer will then distribute among the shareholders of Seller.
NOW, THEREFORE, for good and valuable consideration the receipt and sufficiency of which are hereby acknowledged by the parties to this Agreement, and in light of the above recitals to this Agreement, the parties to this Agree- ment hereby agree as follows:
On the terms and subject to the conditions set forth in this Agreement, Seller agrees to sell, convey, assign, transfer and deliver to Buyer and Buyer agrees to purchase from Seller, at the closing (the "Closing") on August 15, 2003 ("Closing Date"), the following three patents: No. 6,180,871 for Transparent Solar Cell and Method of Fabrication (Device), granted on January 30, 2001; No. 6,320,117 for Transparent Solar Cell and Method of Fabrication (Method of Fabrication), granted on November 20, 2001; and No. 6,509,204 for Transparent Solar Cell and Method of Fabrication (formed with a Schottky barrier diode and method of its manufacture), granted on January 21, 2003 (collectively, the "Patents").
On the Closing Date, Buyer will not assume or be obligated to satisfy or perform any liabilities, obligations or payables of Seller, other than those secured by the Patents.
As consideration for the sale, conveyance, assignment, transfer and delivery of the Patents to Buyer, Buyer agrees to issue to Seller Seventy Million (70,000,000) shares of its Common Stock, (collectively referred to as the "Shares"). Immediately after the Closing, Seller will distribute all of the Shares to its shareholders on a pro rata basis.
The Closing of the exchange will occur upon the satisfaction or waiver of the conditions set forth in Section 7 of this Agreement, but no later than August 15, 2003. At the Closing Seller shall deliver to Buyer such bills of sale, deeds, assignments and other instruments of sale, conveyance, assignment and transfer as are sufficient in the opinion of Buyer and its counsel to vest in Buyer and its successors or assigns the absolute, legal and equitable title to the Patents. Buyer shall deliver to Seller stock certificates representing a total of Seventy Million (70,000,000) shares of Buyer's Common), which may then be distributed in kind in liquidation and the winding down of Seller among its shareholders on a pro rata basis if an exemption from Registration is available therefore. All parties to this Agreement hereby agree to execute all other documents and take all other actions which are reasonably necessary or appropriate in order to effect all of the transactions contemplated by this Agreement.
5. Representations and Warranties of Seller.
Seller represents and warrants to Buyer as follows:
Seller has full power and authority to enter into this Agreement and to perform its obligations hereunder. The execution, delivery and performance of this Agreement by it have been duly authorized by all necessary action on its part. Assuming that this Agreement is a valid and binding obligation of each of the other parties hereto, this Agreement is a valid and binding obligation of Seller.
(a) The execution and delivery of this Agreement and the consummation of the transactions contemplated hereby will not to Seller's knowledge result in a breach of the terms and conditions of, or result in a loss of rights under, or result in the creation of any lien, charge or encumbrance upon, any of the Patents pursuant to (i) Seller's articles of incorporation, (ii) any franchise, mortgage, deed of trust, lease, license, permit, agreement, contract, instrument or undertaking to which Seller is a party or by which it or any of its properties are bound, or (iii) any statute, rule, regulation, order, judgment, award or decree.
(b) Seller has good and marketable title to the Patents free and clear of all mortgages, liens, leases, pledges, charges, encumbrances, equities or claims.
(c) To Seller's knowledge the Patents are not subject to any material liability, absolute or contingent, nor is Seller subject to any liability, absolute or contingent, which has not been disclosed to and acknowledged by Buyer in writing prior to the Closing Date.
(d) To Seller's knowledge no consent is necessary to effect the transfer to Buyer of the Patents and, upon the consummation of the transactions contemplated hereby, Buyer will be entitled to use the Patents to the full extent that Buyer used the same immediately prior to the transfer of the Patents.
(e) Seller will provide copies of its Board Resolutions approving and adopting this Agreement and authorizing the transaction in accordance with this Agreement which shall be acceptable to Buyer.
Neither (a) the execution and delivery of this Agreement, nor (b) the
performance of this Agreement will: (i) contravene or result in a violation of
any of the provisions of the articles of incorporation, bylaws or other charter
or organizational documents of Seller; (ii) contravene or result in a violation
of any resolution adopted by the board of directors or shareholders of Seller;
(iii) result in a violation or breach of, or give any person the right to
declare (whether with or without notice or lapse of time) a default under or to
terminate, any agreement or other instrument to which Seller is a party or by
which Seller or any of its assets are bound; (iv) result in the loss of the
Patents; (v) result in the creation or imposition of any lien, charge,
encumbrance or restriction on any of the Patents; or (vi) result in a violation
of any law, rule, regulation, treaty, ruling, directive, order, arbitration
award, judgment or decree to which Seller or the Patents are subject.
Except for the filing of the assignments of patent with the United States Patent and Trademark Office, no authorization, consent or approval of, or registration or filing with, any governmental authority or any other person is required to be obtained or made by Seller in connection with the execution, delivery or performance of this Agreement.
Seller has not agreed to pay any brokerage fees, finder's fees or other fees or commissions with respect to the transactions contemplated by this Agreement, and, to Seller's knowledge, no person is entitled, or intends to claim that it is entitled, to receive any such fees or commissions in connection with such transaction.
The representations and warranties of Seller set forth in this Agreement are true and correct on the date hereof, and will be true and correct on the Closing Date as though such representations and warranties were made as of the Closing Date.
The shares of Buyer's Common Stock being acquired by the shareholders of Seller pursuant to this Agreement are not being acquired by the shareholders of Seller with a view to the public distribution of them. Seller acknowledges and agrees that the Buyer's Common Stock acquired by the shareholders of Seller pursuant to this Agreement has not been registered or qualified under federal or state securities laws, and may not be sold, conveyed, transferred, assigned or hypothecated without being registered under the Securities Act of 1933, as amended, and applicable state law, or in the alternative submission of evidence reasonably satisfactory to Buyer that an exemption from registration is available. In the event that Seller in liquidation of its asset and winding down of its business, in contemplation of dissolution, distributes its remaining
assets, in kind, pro rata to its shareholders, the Seller shall provide the opinion of its counsel to Buyer that the liquidating distribution is exempt from Registration under the Securities Act of 1935, which opinion shall cite the legal precedents upon which its relies in rendering such opinion.
6. Representations and Warranties of Buyer.
Buyer represents and warrants to Seller as follows:
Buyer has full power and authority to enter into this Agreement and to perform its obligations hereunder. The execution, delivery and performance of this Agreement by Buyer have been duly authorized by all necessary action on its part. Assuming that this Agreement is a valid and binding obligation of each of the other parties hereto, this Agreement is a valid and binding obligation of Buyer.
Buyer (i) is duly organized, validly existing and in good standing under the laws of the jurisdiction in which it is incorporated, (ii) has all necessary power and authority to own its assets and to conduct its business as it is currently being conducted, and (iii) is duly qualified or licensed to do business and is in good standing in every jurisdiction (both domestic and foreign) where such qualification or licensing is required.
Buyer has delivered to Seller complete and correct copies of (i) the
articles of incorporation, bylaws and other charter or organizational documents
of Buyer, including all amendments thereto, (ii) the stock records of Buyer, and
(iii) the minutes and other records of the meetings and other proceedings of the
shareholders and directors of Buyer. Buyer is not in violation or breach of (i)
any of the provisions of its articles of incorporation, bylaws or other charter
or organizational documents, or (ii) any resolution adopted by its shareholders
or directors. There have been no meetings or other proceedings of the
shareholders or directors of Buyer that are not fully reflected in the
appropriate minute books or other written records of Buyer.
The authorized capital stock of Buyer consists of 500,000,000 shares of
common stock, no par value, of which 15,362,970 shares are issued and
outstanding and of which 768,149 shares will be issued and outstanding after the
Buyer effects a one for twenty reverse split of its issued and outstanding
common stock prior to the Closing, and 50,000,000 shares of preferred stock, par
value $0.01, none of which is issued or outstanding. All of the outstanding
shares of the capital stock of Buyer are validly issued, fully paid and
nonassessable, and have been issued in full compliance with all applicable
federal, state, local and foreign securities laws and other laws. There are no
(i) outstanding options, warrants or rights to acquire any shares of the capital
stock or other securities of Buyer, (ii) outstanding securities or obligations
which are convertible into or exchangeable for any shares of the capital stock
or other securities of Buyer, or (iii) contracts or arrangements under which
Buyer is or may become bound to sell or otherwise issue any shares of its
capital stock or any other securities.
Except as otherwise disclosed to Seller in writing prior to the Closing, since March 31, 2003, there has not been any material adverse change in the business, condition, assets, operations or prospects of Buyer and no event has occurred that might have an adverse effect on the business, condition, assets, operations or prospects of Buyer.
The Buyer will have no material liabilities upon the Closing, or on the Closing Date will have adequate cash reserves to pay all liabilities before, on, or as soon as practicable after the Closing Date, and will arrange to have all such liabilities paid from such reserves in the above-described time period. After the Closing Date, certain obligations of the Buyer arising from past services will be paid by issuing 230,000 shares of the of the Buyer's common stock to individual service providers ("Service Providers"). The Buyer has agreed to file Form S-8 to allow the Service Providers to sell 57,500 shares within 90 days of the Closing Date. The Buyer has further agreed to file Form S-8 to allow the Service Providers to sell an additional 57,500 shares within 180 days of the Closing Date.
Buyer has no debt, liability or other obligation of any nature (whether due or to become due and whether absolute, accrued, contingent or otherwise), other than those that have been disclosed to Seller prior to the Closing.
There is no action, suit, proceeding, dispute, litigation, claim, complaint or investigation by or before any court, tribunal, governmental body, governmental agency or arbitrator pending or, to Buyer's knowledge, threatened against or with respect to Buyer which (i) if adversely determined would have an adverse effect on the business, condition, assets, operations or prospects of Buyer, or (ii) challenges or would challenge any of the actions required to be taken by Buyer under this Agreement. There exists no basis for any such action, suit, proceeding, dispute, litigation, claim, complaint or investigation.
Neither (a) the execution and delivery of this Agreement, nor (b) the performance of this Agreement will: (i) contravene or result in a violation of any of the provisions of the articles of incorporation, bylaws or other charter or organizational documents of Buyer; (ii) contravene or result in a violation of any resolution adopted by the shareholders or directors of Buyer; (iii) result in a violation or breach of, or give any person the right to declare (whether with or without notice or lapse of time) a default under or to terminate, any agreement or other instrument to which Buyer is a party or by which Buyer or any of its assets are bound; (iv) give any person the right to accelerate the maturity of any indebtedness or other obligation of Buyer; (v) result in the loss of any license or other contractual right of Buyer; (vi) result in the loss of, or in a violation of any of the terms, provisions or conditions of, any governmental license, permit, authorization or franchise of Buyer; (vii) result in the creation or imposition of any lien, charge, encumbrance or restriction on any of the assets of Buyer; (viii) result in the reassessment or revaluation of any property of Buyer by any taxing authority or
other governmental authority; (ix) result in the imposition of, or subject Buyer to any liability for, any conveyance or transfer tax or any similar tax; or (x) result in a violation of any law, rule, regulation, treaty, ruling, directive, order, arbitration award, judgment or decree to which Buyer or any of its assets is subject.
No authorization, consent or approval of, or registration or filing with, any governmental authority or any other person is required to be obtained or made by Buyer in connection with the execution, delivery or performance of this Agreement.
Buyer has not agreed to pay any brokerage fees, finder's fees or other fees or commissions with respect to the transactions contemplated by this Agreement, and, to Buyer's knowledge, no person is entitled, or intends to claim that it is entitled, to receive any such fees or commissions in connection with such transactions.
Neither this Agreement (including the exhibits hereto) nor any statement, certificate or other document delivered to Seller by or on behalf of Buyer contains any untrue statement of a material fact or omits to state a material fact necessary to make the representations and other statements contained herein and therein not misleading.
The representations and warranties of Buyer set forth in this Agreement are true and correct on the date hereof, and will be true and correct on the Closing Date as though such representations and warranties were made as of the Closing Date.
Buyer's obligation to close the plan of reorganization and exchange as contemplated in this Agreement is conditioned upon the occurrence or waiver by Buyer of the following:
(a) All representations and warranties of Seller made in this Agreement or in any exhibit hereto delivered by Seller shall be true and correct as of the Closing Date with the same force and effect as if made on and as of that date.
(b) Seller shall have performed and complied with all agreements, covenants and conditions required by this Agreement to be performed or complied with by Seller prior to or at the Closing Date.
Seller's obligation to close the plan of reorganization and exchange as contemplated in this Agreement is conditioned upon the occurrence or waiver by Seller of the following:
(a) Buyer shall have caused a one for twenty reverse split of its common stock to take effect prior to the Closing Date such that approximately 768,149 shares of its common stock are issued and outstanding on the Closing Date.
(b) Buyer shall have changed its company name to XsunX, Inc. on or before the Closing Date.
(c) Buyer shall have entered into that certain board change agreement (the "Board Change Agreement"), a copy of which is attached to this Agreement as Exhibit B, pursuant to which Mr. Brian Altounian will become the Chief Executive Officer, President, Chief Financial Officer, Secretary, and Chairman of Buyer and will be issued 20,000,000 shares of Buyer's common stock, effective as of the Closing Date.
(d) Buyer shall have completed the private placement of 13,000,000 shares of the Buyer's common stock at a purchase price of $0.025 per share.
(e) Holders of at least 75% of the outstanding shares of common stock of Seller shall vote for and approve this plan of reorganization, and no more than 10% of the holders of outstanding shares of common stock shall disapprove of this plan of reorganization.
(f) All representations and warranties of Buyer made in this Agreement or in any exhibit hereto delivered by Buyer shall be true and correct on and as of the Closing date with the same force and effect as if made on and as of that date.
(g) Buyer shall have performed and complied with all agreements and conditions required by this Agreement to be performed or complied with by Buyer prior to or at the Closing Date.
Following the Closing, Seller agrees to take such actions and execute, acknowledge and deliver to Buyer such further instruments of assignment, assumptions, conveyance and transfer and take any other action as Buyer may reasonably request in order to more effectively convey, sell, transfer and assign to Buyer the Patents, to confirm the title of Buyer thereto, and to assist Buyer in exercising its rights with respect to the Patents.
All representations and warranties made by each of the parties hereto shall survive the closing for a period of one year after the Closing Date.
Seller agrees to indemnify, defend and hold harmless Buyer and its affiliates against any and all claims, demands, losses, costs, expenses, obligations, liabilities and damages, including interest, penalties and attorney's fees and costs, incurred by Buyer arising, resulting from, or relating to any and all liabilities of Seller, other than those secured by the Patents, or any breach of, or failure by Seller to perform, any of its representations, warranties, covenants or agreements in this Agreement or in any
exhibit or other document furnished or to be furnished by Seller under this Agreement.
Buyer agrees to indemnify, defend and hold harmless Seller and its affiliates against any and all claims, demands, losses, costs, expenses, obligations, liabilities and damages, including interest, penalties and attorneys' fees and costs incurred by Seller arising, resulting from or relating to any breach of, or failure by Buyer to perform, any of its representations, warranties, covenants or agreements in this Agreement or in any exhibit or other document furnished or to be furnished by Buyer under this Agreement.
Each party acknowledges that it would be impossible to measure in money the damages to the other party if there is a failure to comply with any covenants and provisions of this Agreement, and agrees that in the event of any breach of any covenant or provision, the other party to this Agreement will not have an adequate remedy at law.
It is therefore agreed that the other party to this Agreement who is entitled to the benefit of the covenants and provisions of this Agreement which have been breached, in addition to any other rights or remedies which they may have, shall be entitled to immediate injunctive relief to enforce such covenants and provisions, and that in the event that any such action or proceeding is brought in equity to enforce them, the defaulting or breaching party will not urge a defense that there is an adequate remedy at law.
If any party shall at any time waive any rights hereunder resulting from any breach by the other party of any of the provisions of this Agreement, such waiver is not to be construed as a continuing waiver of other breaches of the same or other provisions of this Agreement. Resort to any remedies referred to herein shall not be construed as a waiver of any other rights and remedies to which such party is entitled under this Agreement or otherwise.
Each covenant and representation of this Agreement shall inure to the benefit of and be binding upon each of the parties, their personal representatives, assigns and other successors in interest.
This Agreement constitutes the entire agreement between the parties and supersedes all other agreements, representations, warranties, statements, promises and undertakings, whether oral or written, with respect to the subject matter of this Agreement. This Agreement may be modified or amended only by a written agreement signed by the parties against whom the amendment is sought to be enforced.
This Agreement shall be governed by and construed in accordance with the laws of the State of California, and the venue for any action hereunder shall be in the appropriate forum in the County of Los Angeles, State of California.
This Agreement may be executed simultaneously in any number of counterparts, each of which counterparts shall be deemed to be an original, and such counterparts shall constitute but one and the same instrument.
In the event that either party must resort to legal action in order to enforce the provisions of this Agreement or to defend such action, the prevailing party shall be entitled to receive reimbursement from the nonprevailing party for all reasonable attorneys' fees and all other costs incurred in commencing or defending such action, or in enforcing this Agreement, including but not limited to post judgment costs.
This Agreement shall not be assignable by any party without prior written consent of the other parties.
Except as otherwise expressly provided herein, none of the remedies set forth in this Agreement are intended to be exclusive, and each party shall have all other remedies now or hereafter existing at law, in equity, by statute or otherwise. The election of any one or more remedies shall not constitute a waiver of the right to pursue other available remedies.
The section headings in this Agreement are included for convenience only, are not a part of this Agreement and shall not be used in construing it.
In the event that any provision or any part of this Agreement is held to be illegal, invalid or unenforceable, such illegality, invalidity or unenforceability shall not affect the validity or enforceability of any other provision or part of this Agreement.
Each notice or other communication hereunder shall be in writing and shall be deemed to have been duly given on the earlier of (i) the date on which such notice or other communication is actually received by the intended
recipient thereof, or (ii) the date five (5) days after the date such notice or other communication is mailed by registered or certified mail (postage prepaid) to the intended recipient at the following address (or at such other address as the intended recipient shall have specified in a written notice given to the other parties hereto):
Xoptix, Inc.
233 Wilshire Blvd., Suite 820
Santa Monica, CA 90401
Attention: Douglas O'Rear, President
Telephone: (310) 393-9992 Facsimile: (310) 393-2004
Sun River Mining, Inc.
7609 Ralston Road
Arvada, Colorado 80002
Attention: Thomas Anderson, Chief Executive Officer
Telephone: (303) 422-8127 Facsimile: (303) 431-1567
No press release, notice to any third party or other publicity concerning the transactions contemplated by this Agreement shall be issued, given or otherwise disseminated without the prior approval of each of the parties hereto; provided, however, that such approval shall not be unreasonably withheld.
IN WITNESS WHEREOF, this Agreement has been entered into as of the date first above written.
Seller: XOPTIX, INC., a California corporation
By: /s/ Douglas O'Rear
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Douglas O'Rear, President
Buyer: SUN RIVER MINING, INC., a Colorado corporation
By: /s/ Thomas Anderson
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Thomas Anderson, Chief Executive Officer
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EXHIBIT A
ASSIGMENTS OF PATENTS
ASSIGNMENT OF PATENT
WHEREAS, the undersigned (the "Patentee") did obtain a United States Patent for Transparent Solar Cell and Method of Fabrication (Device), No. 6,180,871, dated January 30, 2001 (the "Patent");
WHEREAS, the Patentee is the sole owner of the Patent;
WHEREAS, XsunX, Inc., a Colorado corporation previously named Sun River Mining, Inc. (the "Assignee") whose mailing address is _________, desires to acquire the entire right, title, and interest in and to the Patent.
NOW THEREFORE, in consideration for the sum of one dollar ($1.00), shares of the common stock of the Assignee and other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the Patentee does hereby sell, assign, and transfer to the Assignee the entire right, title, and interest in and to the Patent to be held and enjoyed by the Assignee for its own use and on its own behalf, and for its legal representatives and assigns, to the full end of the term for which the Patent has been granted, as fully and entirely as the Patent would have been held by the Patentee had this assignment and sale not been made.
Executed this 15th day of August 2003 at Los Angeles, California.
XOPTIX, INC.
By: /s/ Douglas O'Rear
---------------------------------
Douglas O'Rear, President
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State of )
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County of )
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Before me personally appeared said
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and acknowledge that the foregoing instrument to be his free act and deed this _____ day of __________, 2003
ASSIGNMENT OF PATENT
WHEREAS, the undersigned (the "Patentee") did obtain a United States Patent for Transparent Solar Cell and Method of Fabrication (Method of Fabrication), No. 6,320,117, dated November 20, 2001 (the "Patent");
WHEREAS, the Patentee is the sole owner of the Patent;
WHEREAS, XsunX, Inc., a Colorado corporation previously named Sun River Mining, Inc. (the "Assignee") whose mailing address is _________, desires to acquire the entire right, title, and interest in and to the Patent.
NOW THEREFORE, in consideration for the sum of one dollar ($1.00), shares of the common stock of the Assignee and other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the Patentee does hereby sell, assign, and transfer to the Assignee the entire right, title, and interest in and to the Patent to be held and enjoyed by the Assignee for its own use and on its own behalf, and for its legal representatives and assigns, to the full end of the term for which the Patent has been granted, as fully and entirely as the Patent would have been held by the Patentee had this assignment and sale not been made.
Executed this 15th day of August 2003 at Los Angeles, California.
XOPTIX, INC.
State of )
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County of )
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Before me personally appeared said
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and acknowledge that the foregoing instrument to be his free act and deed this _____ day of __________, 2003
ASSIGNMENT OF PATENT
WHEREAS, the undersigned (the "Patentee") did obtain a United States Patent for Transparent Solar Cell and Method of Fabrication (formed with a Schottky barrier diode and method of its manufacture), No. 6,509,204, dated January 21, 2003 (the "Patent");
WHEREAS, the Patentee is the sole owner of the Patent;
WHEREAS, XsunX, Inc., a Colorado corporation previously named Sun River Mining, Inc. (the "Assignee") whose mailing address is _________, desires to acquire the entire right, title, and interest in and to the Patent.
NOW THEREFORE, in consideration for the sum of one dollar ($1.00), shares of the common stock of the Assignee and other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the Patentee does hereby sell, assign, and transfer to the Assignee the entire right, title, and interest in and to the Patent to be held and enjoyed by the Assignee for its own use and on its own behalf, and for its legal representatives and assigns, to the full end of the term for which the Patent has been granted, as fully and entirely as the Patent would have been held by the Patentee had this assignment and sale not been made.
Executed this 15th day of August 2003 at Los Angeles, California.
XOPTIX, INC.
State of )
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County of )
-------------------------------------------
Before me personally appeared said
-------------------------------------
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and acknowledge that the foregoing instrument to be his free act and deed this _____ day of __________, 2003
EXHIBIT B
BOARD CHANGE AGREEMENT
OF
SUN RIVER MINING, INC.
BOARD CHANGE AGREEMENT
This BOARD CHANGE AGREEMENT (this "Agreement") is made as of the 9th day of July 2003, by and between Sun River Mining, Inc., a Colorado corporation to be renamed XSunX, Inc. (the "Company"), Stephen W. Weathers, an individual ("Weathers"), Randy A. McCall, an individual ("McCall"), Thomas Anderson, an individual ("Anderson"), and Brian Altounian, an individual ("Altounian"), and is made with respect to the following facts:
R E C I T A L S
A. The current members of the Board of Directors of the Company are Weathers, McCall, and Anderson (collectively, the "Current Board").
B. Weathers is the current Secretary of the Company and Anderson is the current Chief Executive Officer of the Company (collectively, the "Current Officers").
C. It is the intent of the parties that all members of the Current Board and all Current Officers resign and that Altounian be appointed Chairman, Chief Executive Officer, and Chief Financial Officer, of the Company, on the terms and subject to the conditions set forth in this Agreement (such change in Board composition is referred to herein as the "Board Change" and such change in the officers of the Company is referred to herein as the "Officer Change"). Thus, upon satisfaction of these conditions and the completion of the matters set forth in this Agreement, the sole member of the Company's Board of Directors will be Altounian (the "New Board") and the sole officer of the Company will be Altounian (the "New Officer").
NOW, THEREFORE, in consideration of the premises and mutual covenants herein contained, THE PARTIES HERETO AGREE AS FOLLOWS:
1. Resignation of Directors and Officers
1.1 Resignation of Directors. Subject to the terms and conditions of this Agreement, at the Effective Time (as defined in Section 2 of this Agreement), the resignations of Weathers, McCall, and Anderson from the Company's Board of Directors shall be effective.
1.2 Appointment of Director. Subject to the terms and conditions of this Agreement, immediately following the Effective Time, the appointment to the Board of Altounian shall be effective.
1.3 Resignation of Officers. Subject to the terms and conditions of this Agreement, at the Effective Time (as defined in Section 2 of this Agreement), the resignations of Weathers and Anderson as the Secretary and Chief Executive Officer, respectively, of the Company's Board of Directors shall be effective.
1.4 Appointment of Officers. Subject to the terms and conditions of this Agreement, immediately following the Effective Time, the appointment of Altounian as the Chief Executive Officer, President, and Chief Financial Officer, of the Company shall be effective.
1.5 Number of Directors. Following the Closing, the New Board may, but shall be under no obligation to, appoint additional members of the Board who may be identified from time to time, all in accordance with the Company's organizational documents.
1.6 Additional Officers. Following the Closing, the New Board may, but shall be under no obligation to, appoint additional officers to assist the New Officer.
2. Closing
At 5:00 p.m. pacific daylight time on August 15, 2003, provided the conditions in Sections 6 and 7 of this Agreement have been satisfied or waived in writing, or at such later time and date as Altounian and the Current Board may agree (the "Effective Time"), the conditional resignations of Weather, McCall, and Anderson as directors and officers of the Company, as the case may be, shall be in effect and no longer subject to any condition and, immediately thereafter the appointment of Altounian as a director, Chief Executive Officer, President, and Chief Financial Officer, of the Company shall be in effect and no longer subject to any condition (such resignation and appointment, the "Closing"). On or before the Effective Time on the date of the Closing (the "Closing Date"), the Current Board shall deliver to Altounian such documents as may be reasonably requested by Altounian, including documents evidencing the satisfaction of the conditions set forth in this Agreement that are within the possession or control of the Company or the Current Board. On or before the Effective Time on the date of the Closing (the "Closing Date"), Altounian shall deliver to the Current Board such documents as may be reasonably requested by the Company and the Current Board, including documents evidencing the satisfaction of the conditions set forth in this Agreement that are within the possession or control of Altounian.
3. Representations and Warranties
3.1 Representations of Individuals. Each individual who is a party to this Agreement represents and warrants to all other parties to this Agreement as follows:
(a) this Agreement constitutes the legal, valid,
and binding obligation of such person, enforceable against such person in accord
- -ance with its terms; and
(b) the description of such individual and any other matters between such individual and the Company to be contained in the Information Statement (as defined in Section 6.2 of this Agreement) and any other information supplied in writing by such individual to the Company for inclusion in the Information Statement will be complete and accurate in all material respects when made and at the Closing, and will not contain any untrue statement of material fact or omit to state a material fact required to be stated therein or necessary to made the statements therein, in light of the circumstances under which they were made, not misleading.
3.2 Representations of Company. The Company represents and warrants to all other parties to this Agreement as follows:
(a) it is a corporation duly organized, validly existing and in good standing under the laws of the State of Colorado, having all corporate powers to execute, deliver, and perform its obligations under this Agreement;
(b) the execution, delivery, and performance by the Company of this Agreement and the consummation of the transactions con- templated hereby are within the Company's corporate powers and has been duly authorized by all necessary corporate action;
(c) this Agreement has been duly executed and delivered by the Company and constitutes the legal, valid, and binding obliga- tion of the Company, enforceable against the Company in accordance with its terms; and
(d) neither the execution and delivery of this Agreement nor the consummation and performance of any of the Board Change and Officer Change will, directly or indirectly (with or without notice or lapse of time) contravene, conflict with, or result in a violation of any provision of the company organizational documents or any resolutions adopted by the board of directors or the shareholders of the Company or (ii) contravene, conflict with, or result in a violation or breach of any provision of, or give any person the right to declare a default or exercise any remedy under, or to accelerate the maturity or performance of, or to cancel, terminate, or modify any agreement to which the Company is a party or by which the Company is bound.
4. Covenants of Company and Current Board Prior to Closing
4.1 Required Approvals. From the date of this Agreement until the Effective Time, the Company and the Current Board shall make and shall cooperate with Altounian to make all filings required by law in connection with the Board Change or any other matter contemplated under this Agreement. From the date of this Agreement until the Effective Time, the Company and the Current Board shall use commercially reasonable efforts to cause the conditions set forth in Sections 6 and 7 of this Agreement to be satisfied, including but not limited to filing the Notice to Shareholders to all shareholders of record, and mailing an amendment to the Company's Articles of Incorporation with the Colorado Secretary of State to change the name of the Company from Sun River Mining, Inc. to XSunX, Inc. and to effect a twenty-to-one reverse split of the Company's common stock.
4.2 Stand Still. From the date of this Agreement until the Effective Time (the "Stand Still Period"), unless Altounian otherwise consents in writing, the Company shall not initiate on its own or solicit or encourage any inquiries or proposals from, discuss or negotiate with, provide non-public information to, or consider any unsolicited inquiries from any third party, in connection with any of the following:
(a) any amendment of the organizational docu- ments of the Company;
(b) any extraordinary corporate transaction (merger, sale of assets, sale of securities or other similar transaction, declaration of dividend or adoption of shareholders rights plan) or any agree- ment to incur any material liability (loans for borrowed money); or
(c) any increase or agreement to increase compensation payable to directors, employees or consultants, or enter into severance or termination arrangements affecting directors, consultants, or employees or any amendment to any employee plans or any grant of any options, warrants, or rights to purchase securities of the Company.
5. Covenants of Altounian Prior to Closing
From the date of this Agreement until the Effective Time, Altounian shall cooperate with the Company to make all filings required by law in connection with the Board Change or any other matter contemplated under this Agreement. From the date of this Agreement until the Effective Time, Altounian shall use commercially reasonable efforts to cause the conditions set forth in Sections 6 and 7 of this Agreement to be satisfied.
6. Conditions Precedent to the Company's and Current Board's Obligation to Close
The Company's and Current Board's obligation to effect the Board Change and take such other actions required to be taken by the Company and Current Board at the Closing is subject to the satisfaction, at or prior to the
Closing, of each of the following conditions (any of which may be waived by the Company and Current Board, in whole or in part):
6.1 Completion of Private Placement. Altounian shall have completed the private placement of 13,000,000 shares of the Company's common stock at a purchase price of $0.025 per share (the "Offering").
6.2 Notice to Shareholders. The Company shall have filed and mailed an Information Statement (the "Notice to Shareholders") in accordance with Rule 14f-1 under the Securities Exchange Act of 1934, as amended (the "Act"). The ten-day waiting period required under Rule 14f-1 under the Act following the mailing of the Notice to Shareholders shall have lapsed.
6.3 Name Change. The Company shall have filed an amend- ment with the Colorado Secretary of State to change the name of the Company from Sun River Mining, Inc. to XSunX, Inc. The amendment shall have been recorded with the Colorado Secretary of State.
6.4 Reverse Stock Split. The Company shall have filed an amendment with the Colorado Secretary of State to effect a twenty-to-one reverse split of the Company's common stock. The amendment shall have been recorded with the Colorado Secretary of State.
6.5 Assignment of Patents. The Company shall have filed assignments of patents with the United States Patent and Trademark Office for the following three patents: No. 6,180,871 for Transparent Solar Cell and Method of Fabrication (Device), granted on January 30, 2001; No. 6,320,117 for Transparent Solar Cell and Method of Fabrication (Method of Fabrication), granted on November 20, 2001; and No. 6,509,204 for Transparent Solar Cell and Method of Fabrication (formed with a Schottky barrier diode and method of its manufacture), granted on January 21, 2003 (collectively, the "Patents").
6.6 Issuance of Stock. The Company shall have issued 20,000,000 shares of the Company's common stock to Altounian or his designees, 10,500,000 shares of the Company's common stock to Corporate Strategies, Inc. or its designees, 400,000 shares of the Company's common stock to Sam Spear or his designees, 400,000 shares of the Company's common stock to Gary Stephenson or his designees.
6.7 Accuracy of Representations. All of the representations and warranties of Altounian set forth in this Agreement shall have been accurate in all material respects as of the date of this Agreement and shall be accurate in all material respects as of the Effective Time as if made on the Effective Time.
6.8 Performance of Covenants. Each of the covenants and obligations that Altounian is required to perform or to comply with pursuant to this Agreement at or prior to Closing shall have been duly performed and complied with in all material respects.
6.9 No Legal Proceedings. No decree, injunction, judgment, order, ruling, assessment or writ (collectively, "Order") shall have been declared, entered, issued, or enforced by any governmental entity which prohibits or restricts (or if successful, would prohibit or restrict) the Board Change or other transactions contemplated in this Agreement.
7. Conditions Precedent to Altounian's Obligation to Close
Altounian's obligation to effect the Board Change and take such other actions required to be taken by Altounian at the Closing is subject to the satisfaction, at or prior to the Closing, of each of the following conditions (any of which may be waived by Altounian, in whole or in part):
7.1 Approval and Conditional Appointment of Altounian. Altounian and any executive officer proposed by the New Board to have positions with the Company at or immediately following the Effective Time and who must be identified in the Information Statement referred to in Section 6.2 of this Agreement must have been disclosed to and approved by the Current Board, such approval not to be unreasonably withheld. The Current Board shall have approved resolutions at a meeting of the Current Board duly held in accordance with the Bylaws which provide for the appointment of Altounian as a director of the Board, such appointment to be effective at the Effective Time.
7.2 Notice to Shareholders. The Company shall have filed and mailed the Notice to Shareholders in accordance with Rule 14f-1 under the Act. The ten-day waiting period required under Rule 14f-1 under the Act following the mailing of the Notice to Shareholders shall have lapsed.
7.3 Name Change. The Company shall have filed an amend- ment with the Colorado Secretary of State to change the name of the Company from Sun River Mining, Inc. to XSunX, Inc. The amendment shall have been recorded with the Colorado Secretary of State.
7.4 Reverse Stock Split. The Company shall have filed an amendment with the Colorado Secretary of State to effect a twenty-to-one reverse split of the Company's common stock. The amendment shall have been recorded with the Colorado Secretary of State.
7.5 Assignment of Patents. The Company shall have filed assignments of patents with the United States Patent and Trademark Office for the Patents.
7.6 Issuance of Stock. The Company shall have issued 20,000,000 shares of the Company's common stock to Altounian or his designees, 10,500,000 shares of the Company's common stock to Corporate Strategies, Inc. or its designees, 400,000 shares of the Company's common stock to Sam Spear or his designees, 400,000 shares of the Company's common stock to Gary Stephenson or his designees.
7.7 Accuracy of Representations. All of the representations and warranties of the Company and the Current Board set forth in this Agreement shall have been accurate in all material respects as of the date of this Agreement and shall be accurate in all material respects as of the Effective Time as if made on the Effective Time.
7.8 Performance of Covenants. Each of the covenants and obligations that the Company and the Current Board are required to perform or to comply with pursuant to this Agreement at or prior to Closing shall have been duly performed and complied with in all material respects.
7.9 No Legal Proceedings. No decree, injunction, judgment, order, ruling, assessment or writ (collectively, "Order") shall have been declared, entered, issued, or enforced by any governmental entity which prohibits or restricts (or if successful, would prohibit or restrict) the Board Change or other transactions contemplated in this Agreement.
8. Notice
Except as otherwise specifically provided, any notices to be given hereunder shall be deemed given upon personal delivery, air courier or mailing thereof, if mailed by certified mail, return receipt requested, to the following addresses (or to such other address or addresses as shall be specified in any notice given):
In case of the Company:
Sun River Mining, Inc. 7609 Ralston Road Arvada, Colorado 80002 Attention: Thomas Anderson, Chief Executive Officer
Telephone: (303) 422-8127 Facsimile: (303) 431-1567
In case of the individuals:
The address listed below each individuals signature to this Agreement.
9. Attorneys' Fees
In the event that any of the parties must resort to legal action in order to enforce the provisions of this Agreement or to defend such suit, the prevailing party shall be entitled to receive reimbursement from the nonprevailing party for all reasonable attorneys' fees and all other costs incurred in commencing or defending such suit.
10. Entire Agreement
This Agreement embodies the entire understanding among the parties and merges all prior discussions or communications among them, and no party shall be bound by any definitions, conditions, warranties, or representations other than as expressly stated in this Agreement or as subsequently set forth in a writing signed by the duly authorized representatives of all of the parties hereto.
11. Injunctive Relief
11.1 Damages Inadequate. Each party acknowledges that it would be impossible to measure in money the damages to the other party if there is a failure to comply with any covenants and provisions of this Agreement, and agrees that in the event of any breach of any covenant or provision, the other party to this Agreement will not have an adequate remedy at law.
11.2 Injunctive Relief. It is therefore agreed that the other party to this Agreement who is entitled to the benefit of the covenants and provisions of this Agreement which have been breached, in addition to any other rights or remedies which they may have, shall be entitled to immediate injunctive relief to enforce such covenants and provisions, and that in the event that any such action or proceeding is brought in equity to enforce them, the defaulting or breaching party will not urge a defense that there is an adequate remedy at law.
12. No Oral Change; Amendment
This Agreement may only be changed or modified and any provision hereof may only be waived by a writing signed by the party against whom enforcement of any waiver, change or modification is sought. This Agreement may be amended only in writing by mutual consent of the parties.
13. Severability
In the event that any provision of this Agreement shall be void or unenforceable for any reason whatsoever, then such provision shall be stricken and of no force and effect. The remaining provisions of this Agreement shall, however, continue in full force and effect, and to the extent required, shall be modified to preserve their validity.
14. Applicable Law
This Agreement shall be construed as a whole and in accordance with its fair meaning. This Agreement shall be interpreted in accordance with the laws of the State of Los Angeles, and venue for any action or proceedings brought with respect to this Agreement shall be in the County of Los Angeles in the State of California.
15. Successors and Assigns
Each covenant and condition of this Agreement shall inure to the benefit of and be binding upon the parties hereto, their respective heirs, personal representatives, assigns and successors in interest. Without limiting the generality of the foregoing sentence, this Agreement shall be binding upon any successor to the Company whether by merger, reorganization or otherwise.
16. Counterparts
This Agreement may be executed in two counterparts, each of which may be deemed an original, but both of which together shall constitute one and the same agreement.
IN WITNESS WHEREOF, the parties hereto have executed this Agreement on the date first above written.
COMPANY: SUN RIVER MINING, INC., a Colorado corporation
By:
----------------------------------------------------
Thomas Anderson, Chief Executive Officer
Attest:
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Stephen W. Weathers, Secretary
[signatures continued on page 9]
[signatures continued from page 8]
ASSIGNMENT OF PATENT
WHEREAS, the undersigned (the "Patentee") did obtain a United States Patent for Transparent Solar Cell and Method of Fabrication (Method of Fabrication), No. 6,320,117, dated November 20, 2001 (the "Patent");
WHEREAS, the Patentee is the sole owner of the Patent;
WHEREAS, XsunX, Inc., a Colorado corporation previously named Sun River Mining, Inc. (the "Assignee") whose mailing address is 7609 Ralston Road, Arvada, CO 80002, desires to acquire the entire right, title, and interest in and to the Patent.
NOW THEREFORE, in consideration for the sum of one dollar ($1.00), shares of the common stock of the Assignee and other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the Patentee does hereby sell, assign, and transfer to the Assignee the entire right, title, and interest in and to the Patent to be held and enjoyed by the Assignee for its own use and on its own behalf, and for its legal representatives and assigns, to the full end of the term for which the Patent has been granted, as fully and entirely as the Patent would have been held by the Patentee had this assignment and sale not been made.
Executed this 25th day of September 2003 at Camarillo California.
XOPTIX, INC.
State of )
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County of )
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Before me personally appeared said
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and acknowledge that the foregoing instrument to be his free act and deed this 25th day of September, 2003
(Notary Public)
Seal
ASSIGNMENT OF PATENT
WHEREAS, the undersigned (the "Patentee") did obtain a United States Patent for Transparent Solar Cell and Method of Fabrication (formed with a Schottky barrier diode and method of its manufacture), No. 6,509,204, dated January 21, 2003 (the "Patent");
WHEREAS, the Patentee is the sole owner of the Patent;
WHEREAS, XsunX, Inc., a Colorado corporation previously named Sun River Mining, Inc. (the "Assignee") whose mailing address is 7609 Ralston Road, Arvada, CO 80002, desires to acquire the entire right, title, and interest in and to the Patent.
NOW THEREFORE, in consideration for the sum of one dollar ($1.00), shares of the common stock of the Assignee and other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the Patentee does hereby sell, assign, and transfer to the Assignee the entire right, title, and interest in and to the Patent to be held and enjoyed by the Assignee for its own use and on its own behalf, and for its legal representatives and assigns, to the full end of the term for which the Patent has been granted, as fully and entirely as the Patent would have been held by the Patentee had this assignment and sale not been made.
Executed this 25th day of September 2003 at Camarillo California.
XOPTIX, INC.
State of )
--------------------------------------------
County of )
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Before me personally appeared said
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and acknowledge that the foregoing instrument to be his free act and deed this 25th day of September, 2003
(Notary Public)
Seal
CERTIFICATE OF AMENDMENT
OF
ARTICLES OF INCORPORATION
OF
SUN RIVER MINING, INC.
The undersigned President and Secretary of SUN RIVER MINING, INC., Inc., a Colorado corporation (the "corporation") do hereby certify that:
The Shareholders of said corporation at a meeting duly convened on July 3, 2003, adopted resolutions to amend the Articles of Incorporation, as follows:
ARTICLE I shall be amended to change the name to XSUNX, INC., Inc.
ARTICLE I
ARTICLE IV is hereby amended to add the Section 5 as follows:
ARTICLE IV
Section 5: "Reverse Stock Split. Each share of the Corporation's Common Stock, issued and outstanding immediately prior to October 5, 2003 (the "Old Common Stock") shall automatically and without any action on the part of the holder thereof be reclassified as and changed, pursuant to a reverse stock split (the "Reverse Stock split"), into a fraction thereof of 1/20 of a share of the Corporation's outstanding Common Stock, no par value (the "New Common Stock"), subject to the treatment of fractional share interests as described below. Each holder of a certificate or certificates which immediately prior to the October 5, 2003 represented outstanding shares of Old Common Stock (the "Old Certificates," whether one or more) shall be entitled to receive, upon surrender of such Old Certificates to the Corporation's Transfer Agent for cancellation, a certificate or certificates (the "New Certificates," whether one or more) representing the number of whole shares of the New Common Stock into which and for which the shares of the Old Common Stock formerly represented by such Old Certificates so surrendered are classified under the terms hereof. From and after the October 5, 2003, Old Certificates shall represent only the right to receive New Certificates pursuant to the provisions hereof. No certificates or scrip representing fractional share interests in New Common Stock will be issued, and no such fractional share interest will entitle the holder thereof to vote, or to any rights of a shareholder of the Corporation. Any fraction of a share of New Common Stock to which the holder would otherwise be entitled will be adjusted upward to the nearest whole share. If more than one Old Certificate shall be surrendered at one time for the account of the same Shareholder the number of full shares of New Common Stock for which New Certificates shall be issued shall be computed on the basis of the aggregate number of shares represented by the Old certificates so surrendered. In the event that the Corporation's Transfer Agent determines that a holder of Old Certificates has not tendered all his certificates for exchange, the Transfer Agent shall carry forward any fractional share until all certificates of that holder have been presented for exchange such that for fractional shares may be aggregated to a full share, if applicable. If any New Certificate is to be issued in a name other than that in which the Old Certificates surrendered for exchange are issued, the Old Certificates so surrendered shall be properly endorsed and
otherwise in proper form for transfer. From and after the October 5, 2003, the amount of capital represented by the shares of the New Common Stock into which and for which the shares of the Old Common Stock are reclassified under the terms hereof shall be the same as the amount of capital represented by the shares of Old Common Stock so reclassified until after reduced or increased in accordance with applicable law. Fractional shares will be issued."
The number of common shares of the Corporation outstanding and entitled to vote on the Amendments to the Articles of Incorporation was 15,352,970 shares as of July 3, 2003. The above changes and amendments have been approved by a vote of a majority of stockholders attending a meeting at which a quorum was present of the class of stock outstanding and entitled to vote thereon.
The amendments to the Articles of Incorporation were approved by the Board of Directors on June 13, 2003.
Dated: September 30, 2003
SUN RIVER MINING, INC.
By: /s/ Tom Anderson By: /s/ Steve Weathers
------------------------ -----------------------
President Secretary
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United States Patent 6,320,117 Campbell , et al. November 20, 2001 Transparent solar cell and method of fabrication
Abstract
A transparent solar cell and method of manufacture. The method includes steps of providing a transparent substrate. The method also includes forming a first conductive layer overlying the substrate. The method also includes forming a first amorphous silicon layer of a first dopant type overlying the first conductive layer. A step of annealing the first amorphous silicon layer is included. The method also forms a second amorphous silicon layer of a second dopant type, and also anneals the second amorphous silicon layer. A second conductive layer is formed overlying the second amorphous silicon layer. A combination of these steps forms a transparent solar cell structure.
Inventors: Campbell; James P. (Atherton, CA); Galyean; Eric W. (Los Altos
Hills, CA); Spreckman;
Harvey R. (Thousand Oaks, CA)
Assignee: Xoptix, Inc. (Woodland Hills, CA)
Appl. No.: 692366
Filed: October 18, 2000
Current U.S. Class: 136/258; 136/245; 136/256; 136/261; 257/51; 257/74; 257/75;
257/461; 438/96; 438/97; 438/98
Intern'l Class: H01L 031/109; H01L 031/045
Field of Search: 136/258 AM,261,258 PC,256,245 257/51,75,461,74 438/97,96,98
[GRAPHIC OMITTED]
References Cited [Referenced By]
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U.S. Patent Documents
4059461 Nov., 1977 Fan et al. 438/92.
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4214918 Jul., 1980 Gat et al. 438/618.
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4400577 Aug., 1983 Spear 136/259.
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4663495 May., 1987 Berman et al. 136/248.
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4824489 Apr., 1989 Cogan et al. 136/256.
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5192991 Mar., 1993 Hosokawa 136/258.
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5413959 May., 1995 Yamamoto et al. 438/98.
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5667597 Sep., 1997 Ishihara 136/258.
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5714404 Feb., 1998 Mitlitsky et al. 439/97.
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5886688 Mar., 1999 Fifield et al. 345/206.
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6180871 Jan., 2001 Campbell et al. 136/258.
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Primary Examiner: Diamond; Alan
Attorney, Agent or Firm: Townsend and Townsend and Crew LLP
Parent Case Text
CROSS REFERENCE TO RELATED APPLICATIONS
This is a division of U.S. application Ser. No. 09/343,069, filed Jun. 29, 1999, now U.S. Pat. No. 6,180,871 the specification of which is incorporated herein by reference for all purposes.
Claims
What is claimed is:
1. A method of forming a solar cell comprising:
providing a substrate;
forming a first layer of conductive material overlying the substrate;
forming a second layer of amorphous silicon of a first dopant type overlying the first layer;
annealing the second layer to convert the amorphous silicon of the second layer into polycrystalline silicon;
forming a third layer of amorphous silicon of a second dopant type overlying the second layer forming a p-n junction between the second layer and the third layer;
annealing the third layer to convert the amorphous silicon of the third layer into polycrystalline silicon; and
forming a fourth layer of conductive material overlying the third layer.
2. The method of claim 1 wherein the first dopant type is p+.
3. The method of claim 2 wherein the second dopant type is n-.
4. The method of claim 1 wherein the melting point of the substrate is less than 450.degree. C.
5. The method of claim 1 wherein the first layer is formed by an annealing step.
6. The method of claim 1 wherein the annealing of the second layer is done by applying thermal energy while maintaining the substrate at a temperature of less than 450.degree. C.
7. The method of claim 1 wherein the annealing of the second layer comprises application of thermal energy with a laser.
8. The method of claim 7 wherein the laser is a pulsed Excimer laser.
9. The method of claim 1 wherein the first layer is Indium Tin Oxide.
10. A method for fabricating a structure comprising a transparent solar cell structure, the method comprising:
forming a first layer overlying a transparent substrate;
forming a second layer of amorphous silicon overlying the first layer, the second layer being of a first impurity type;
converting the second layer into polycrystalline silicon;
forming a third layer of amorphous silicon overlying the second layer, the third layer being of a second dopant type forming a p-n junction between the second layer and the third layer;
converting the third layer into polycrystalline silicon; and
forming a fourth layer of conductive material overlying the third layer.
11. The method of claim 10 wherein the first layer, the second layer, the third layer, and the fourth layer define a solar cell device.
12. The method of claim 10 wherein the second layer includes a thickness of 1000 .ANG. and less, which provides a transparent structure.
13. The method of claim 10 wherein the third layer includes a thickness of 1000 .ANG. and less, which provides a transparent structure.
14. The method of claim 10 wherein the converting of the second layer is provided using a rapid thermal anneal process, the rapid thermal anneal process maintaining a temperature of less than about 450.degree. C. at the transparent substrate.
15. The method of claim 10 wherein the converting of the third layer is provided using a rapid thermal anneal process, the rapid thermal anneal process maintaining a temperature of less than about 450.degree. C. at the transparent substrate.
16. The method of claim 10 wherein the converting of the second layer is provided using a laser.
17. A method for fabricating a structure comprising a transparent solar cell structure, the method comprising:
providing a substrate;
forming a first layer of conductive material overlying the substrate;
forming a second layer of amorphous silicon overlying the first layer, the second layer being of a first impurity type;
converting the second layer into polycrystalline silicon;
forming a third layer of amorphous silicon overlying the second layer, the third layer being of a second dopant type;
converting the third layer into polycrystalline silicon;
forming a fourth layer of conductive material overlying the third layer;
forming a fifth layer of amorphous silicon overlying the fourth layer;
converting the fifth layer into polycrystalline silicon;
forming a sixth layer of amorphous silicon overlying the fifth layer;
converting the sixth layer into polycrystalline silicon; and
forming a seventh layer of conductive material overlying the sixth layer.
18. The method of claim 17 wherein the converting of at least one of the second, third, fifth and sixth layers is done while maintaining the substrate at a temperature of less than 450.degree. C.
19. The method of claim 17 wherein the converting of each of the second, third, fifth and sixth layers is done while maintaining the substrate at a temperature of less than 450.degree. C.
20. The method of claim 17 wherein the converting of at least one of the second, third, fifth and sixth layers is done using an Excimer laser.
21. The method of claim 17 wherein the third layer directly overlies the second layer with no intervening layers.
22. A solar cell structure comprising:
a substrate with a melting temperature of less than 450.degree. C.;
a first conductive layer overlying the substrate;
a first polycrystalline film overlying the first conductive layer;
a second polycrystalline film overlying the first polycrystalline film;
a second conductive layer overlying the second polycrystalline film;
a third polycrystalline film overlying the second conductive layer;
a fourth polycrystalline film overlying the third polycrystalline film; and
a third conductive layer overlying the fourth polycrystalline film.
23. The solar cell structure of claim 22 wherein the second polycrystalline film directly overlies the first polycrystalline film with no intervening layer.
Description
BACKGROUND OF THE INVENTION
The present invention relates, in general, to electronic devices. More particularly, the present invention provides a transparent solar cell and method of its manufacture.
Solar energy provides many advantages over traditional energy sources. For example, energy from the sun is virtually unlimited and easily accessible throughout the world. It does not require the extraction of a natural resource from the ground to obtain the energy and it can be converted to electricity in a manner that is not harmful to the environment. Solar energy is available whenever the sun is shining and can be collected and stored for use when no light source is available. Therefore, if it can be harnessed economically, it provides an environmentally friendly source of energy that does not deplete or destroy precious natural resources. This is in stark contrast to the use of fossil fuels that are of limited supply and which cause environmental damage with both their use and extraction processes. The use of fossil fuel also requires a constant source of raw materials that may be difficult obtain in many circumstances.
Many different applications benefit greatly from the use of solar energy. For example, buildings and automobiles, with their broad surfaces that are exposed to the sun's energy for much of the day, can use that energy to provide some or all of their energy needs. Various solar cells have been developed using different fabrication techniques to take advantage of this energy source.
One type of solar cell is formed with crystalline silicon. For these solar cells, crystalline silicon is formed by melting silicon and drawing an ingot of crystalline silicon of the size desired. Alternatively, a ribbon of crystalline silicon can be pulled from molton silicon to form a crystalline silicon solar cell. A conductor is placed on either side of the crystalline silicon to form the solar cell. These processes use high temperatures and the solar cells are expensive to manufacture. Packaging is also difficult and expensive and creates a rigid structure. Their maximum size is limited by the manufacturing process. It is difficult to slice the resulting crystalline silicon thin enough to provide a transparent or flexible solar cell. However, these structures are very efficient (relative to other types of presently available commercial solar cells). As such, crystalline solar cells are used primarily for applications where efficiency is more important than cost and where the structures do not need to be flexible. For example, these are commonly used on satellites.
Another type of solar cell is formed with polycrystalline silicon. These may be formed as thin layers on wafers and can thus be made thinner than crystalline silicon solar cells. As is well known in the art, polycrystalline silicon can be formed by heating amorphous silicon. Typically, amorphous silicon begins to crystallize at temperatures greater than about 1400.degree. C. Because of these high temperatures, known processes can only use substrates with high melting points. These processes are not appropriate for substrates made of plastics or other materials that melt at lower temperatures. In the manufacture of flat panel displays, it is known to use
lasers to form polycrystalline silicon thin film transistors (TFTs). Such use has not included the formation of P-N junctions or solar cells which presents its own set of challenges. Moreover, these manufacturing processes generally formed single transistors and were not used to form large sheets or areas of polycrystalline silicon. Further, lasers have been used in the manufacture of solar cells, but only as a tool to mechanically form (slice, pattern, etch, etc.) the solar cells.
Another type of solar cell has been formed using doped layers of amorphous silicon. These are not subject to some of the problems inherent in the previously described crystalline silicon or polycrystalline solar cells. First, amorphous silicon can be formed using low temperature processes. Thus, it can be formed on plastic and other flexible substrates. They can also be formed over large surfaces. Second, the processing techniques are less expensive. Nevertheless, amorphous solar cells introduce other significant limitations not found in crystalline silicon or polycrystalline silicon solar cells. For example, hydrogen is generally added during the manufacturing to increase the efficiency of the cell. Amorphous silicon solar cells tend however to lose this hydrogen over time, causing reduced efficiency and reduced usable life. Moreover, amorphous silicon solar cells are not transparent. Thus, they are not appropriate for many applications. For example, buildings and cars with solar cells can be unsightly, and the solar panels may block the view of the outdoors or access to outside light indoors. Also, portable electronics often place a premium on size and surface area. Some devices have displays that cover most--if not all--of the exposed surface of the device. Therefore, it is often undesirable or impossible to mount a traditional amorphous silicon solar cell on the device.
Attempts have been made to solve this transparency problem by making transparent panels from existing solar cell processes. One method has been to take advantage of the "window shade effect" whereby solar cells are formed on a transparent substrate with gaps between adjacent solar cells. This allows some light to pass through to create a transparent effect. The larger the gaps, the more transparency the device has. A disadvantage of this technique is that much of the space is unused, therefore the efficiency of the device is less than it would be if all of the surface area were used for solar cells. Of course, devices of this type also suffer from the problems inherent to the type of cell used. For example, if based on amorphous silicon, these devices suffer from the hydrogen loss exhibited in other amorphous silicon devices.
Other work has been done at making transparent solar cells using materials other than silicon (for example, cadmium telluride (CdTe)). These cells suffer from the challenges inherit to using materials other than silicon.
Thus, a new solar cell and method of fabrication that will avoid these problems is desirable.
SUMMARY OF THE INVENTION
The present invention provides a solar cell and method of its manufacture. It combines the following advantages: 1) is transparent and therefore can be used in places not applicable to existing solar cells 2) is cost effective because it uses thin film amorphous silicon 3) may be readily manufactured because the method for manufacture uses commercially available CVD and laser annealing equipment and 4) can be used on a wide variety of substrates including low temperature substrates.
According to the present invention, a technique including a method and device for fabricating a solar cell is provided. In an exemplary embodiment, the present invention provides a method and structure which forms a substantially transparent solar cell. The solar cell is thin, flexible, and easy to make and use with conventional semiconductor processes. The solar cell also operates effectively as an optical filter.
In a specific embodiment, the present invention includes a method of forming a solar cell. The method includes steps of providing a substrate, e.g., glass, plastic, Mylar and other substrates, including those with low melting points. The method also includes forming a first conductive layer overlying the substrate. The method also includes forming a first amorphous silicon layer of a first dopant type overlying the first conductive layer. A step of annealing the first amorphous silicon layer is included. The method also forms a second amorphous silicon layer of a second dopant type, and also anneals the second amorphous silicon layer. A second conductive layer is formed overlying the second amorphous silicon layer. A combination of these steps forms a transparent solar cell structure.
In an alternative aspect, the present invention provides a solar cell structure, which is transparent. The structure includes a transparent substrate, which can be selected from glass, crystal, plastic, Mylar, and other substrates, including those that have low melting points. A conductive layer is formed overlying the transparent substrate. A first polycrystalline silicon layer from a first amorphous silicon layer of a first dopant type is formed overlying the first conductive layer. The structure also includes a second polycrystalline silicon layer from a second amorphous silicon layer of a second dopant type overlying the first polycrystalline silicon layer, and a second conductive layer overlying the second polycrystalline silicon layer. The combination of these layers forms a transparent structure.
In a further aspect, the present invention provides a method for fabricating a structure comprising a transparent solar cell structure. The method includes forming a first conductive layer overlying a transparent substrate, and forming a first amorphous silicon layer overlying the first conductive layer. The method also includes converting the first amorphous silicon layer into a first polycrystalline silicon; and forming a second amorphous silicon layer overlying the first amorphous silicon layer. A step of converting the second amorphous silicon layer into a second polycrystalline silicon is included. The method also includes forming a second conductive layer overlying the second amorphous silicon layer. The combination of these steps forms a transparent solar cell structure overlying the substrate.
In still a further aspect, the present invention provides a solar cell comprising a substrate with a melting temperature of less than 450.degree. C., a first conductive layer overlying the substrate, a first polycrystalline film overlying the first conductive layer, a second polycrystalline film overlying the first polycrystalline film, and a second conductive layer overlying the second polycrystalline film.
Numerous advantages are achieved over conventional techniques for forming solar cells. For example, the present method uses conventional equipment and processes from semiconductor operations to manufacture the solar cells. In one aspect of the present invention, an Excimer laser is used to anneal the amorphous silicon layers. Use of this--or a similar laser--allows the forming of polycrystalline silicon without exposing the substrate to high temperature that will distort or destroy it. Therefore, low melting point materials such as plastic may be used. The present solar cells can be transparent, which makes them desirable for placing over glass and other see-through structures. In other aspects, the present invention is easy to implement and control. The present cell structure is extremely thin and efficient and can be implemented on a variety of applications. For example, it can be formed on a flexible substrate and substantially maintain the flexibility of the substrate. Depending upon the embodiment, one or more of these advantages may exist. Other advantages may also exist depending upon the embodiment.
A further understanding of the nature and advantages of the inventions presented herein may be realized by reference to the remaining portions of the specification and the attached drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cross-sectional diagram of a transparent solar cell according to the present invention;
FIG. 2 is a flow diagram showing a method of fabricating solar cells according to the present invention;
FIGS. 3-8 are cross-sectional diagrams of the solar cell of the present
invention at various steps of fabrication; FIG. 9A shows a cross section of the solar cell during an embodiment of annealing process; FIG. 9B shows a thermal graph of the solar cell's temperature through its depth during the annealing process; and FIG. 10 is a cross-sectional diagram of a multiple layer solar cell of the present invention. |
DESCRIPTION OF THE SPECIFIC EMBODIMENTS
FIG. 1 is a cross-sectional diagram of an embodiment of a solar cell 100 according to the present invention. While referred to generically herein as a solar cell, solar cell 100 also may operate efficiently as an optical filter. It may be used as a solar cell exclusively, an optical filter exclusively, or as a combination solar cell and optical filter.
Solar cell 100 may be fabricated in sheets of a size appropriate for its intended use. It may also be fabricated on small substrates or in configurations other than sheets. For example, solar cell 100 may be fabricated as a small device for a hand-held electronic device or on large sheets to be applied to large areas such as windows, buildings and automobiles. In contrast to existing amorphous silicon solar cells, solar cell 100 is transparent. In this context, transparency is defined as having the property of transmitting light without appreciable scattering so that bodies lying beyond are seen clearly. In the specific embodiment, the reflective component is very low; however, the amount of reflection is controllable as will be discussed in more detail below.
Solar cell 100 has a substrate layer 110 providing a base structure for the
device. Substrate layer 110 may be a flexible material or a rigid material
depending on its intended use. A first conductive layer 120 overlies substrate
110. A P-N junction overlies first conductive layer 120. The P-N junction is
formed by a p+doped transparent polycrystalline silicon layer 135 and an n-doped
transparent polycrystalline silicon layer 145. In other embodiments (not shown),
the order is reversed and p+ polycrystalline silicon layer 135 is formed above
n- polycrystalline layer 145. The p+ doped polycrystalline silicon layer 135 and
the n- doped polycrystalline silicon layer 145 may obtain their transparency by
virtue of their method of fabrication as will be described in detail below. A
second conductive layer 150 resides above the P-N junction.
Because of its transparent nature, solar cell 100 can be placed unobtrusively over a variety of surfaces for generating electricity. For example, it can be used as window covering on buildings or automobiles, while maintaining the aesthetics and functionality of the window. Such a window covering can absorb some of the photons from sunlight or other light sources to produce electricity, while allowing those photons not absorbed to pass through to the other side. Thus, the view through the covered window is not completely blocked. Similarly, solar cell 100 can cover a display from a laptop computer or other electronic device such that it can gather light and generate electricity whether the device is in operation or not. Such electronic devices may include portable telephones, laptop computers, palm top computers, electronic watches, etc. While this is a list of some of its applications, it is of course not exhaustive. One can readily identify many applications in which transparent solar cell 100 might be used to generate electricity while not obscuring in any significant degree, the view of the user.
In another embodiment of the present invention, solar cell 100 may operate effectively as an optical filter. In yet another embodiment, it may operate as both a solar cell and an optical filter. It filters out light in undesirable frequencies, while allowing light in the visible frequencies to pass through. Because of its low reflectivity, it may also be used in applications that benefit from anti-reflective coatings. While it is referred to herein generically as solar cell 100, it is specifically intended that the term include its usage as an optical filter as well.
FIG. 2 shows a flow diagram of a method of fabricating solar cell 100 according to the present invention. While FIG. 2 shows a specific embodiment, it is not intended that this be the only way such a transparent solar cell may be fabricated. One of skill in the art will recognize that other variations of the invention are readily apparent from the specific embodiment described herein.
Referring to the flow diagram of FIG. 2, in step 210 a suitable substrate 110 is provided upon which solar cell 100 may be fabricated. FIG. 3 shows a cross-section of the device at step 210 of the fabrication. Substrate 110 may be a rigid or flexible material. For example, flexible substrates such as plastic, Mylar or Polyolifin may be used. Rigid substrates such as glass, crystal, acrylic, or ceramic may also be used. Significantly, substrate 110 need not be a material with a high melting point compared to the temperature at which amorphous silicon crystallizes. Instead, it may include plastics and other materials that have relatively low melting temperatures. This is in stark contrast to previously known crystalline solar cells that required the use of a substrate of a high melting point to withstand the fabrication process. One of skill in the art will recognize many acceptable material for substrate 110 and any may be used without departing from the present invention. The selection of a rigid or flexible substrate 110 is arbitrary except to the extent that a rigid or flexible structure is more appropriate for the end use of solar cell 100. Depending upon the embodiment, substrate 110 may also be coated with a variety of materials. The substrate can also be dyed.
In step 220, a first conductive layer 120 is formed on substrate 110 as depicted in FIG. 4. In the specific embodiment, conductive layer 120 is indium tin oxide (ITO) that is deposited by chemical vapor deposition (CVD). Other materials for conductive layer 120 include magnesium fluoride, aluminum, tungsten, titanium nitride, gold, silver, etc. In an embodiment of the present invention, a flash of silver, aluminum, titanium or other reflective coating may be used to provide a more reflective solar cell. The specific embodiment has an ITO thickness of approximately one half micron over the area of interest; however, other thicknesses may be appropriate for different applications and materials. Its thickness is a function of the desired amount of transparency, conductivity, and flexibility. It may be desirable for conductive layer 120 to be annealed after it has been deposited. Such annealing improves mobility of electrons and holes in conductive layer 120. Conductive layer 120 may also be deposited or formed in other ways besides CVD. First conductive layer 120 may be a single layer or multiple layers, depending upon the embodiment.
In step 225, first conductive layer 120 is optionally cleaned using any of a variety of techniques well known in the art. Such techniques include metal etching, laser scan, etc.
In step 230, a first doped amorphous silicon layer 130 is formed overlying the region of interest of conductive layer 120. The resulting structure is shown in FIG. 5. In the specific embodiment, amorphous silicon layer 130 is a p+ type material. It is in-situ doped using CVD with boron at concentration such as are commonly used for producing solar cells. In other embodiments, amorphous silicon layer 130 may be formed by implantation or diffusion processes. First amorphous silicon layer 130 preferably has a thickness of at least 300 .ANG. at its thinnest points and a nominal thickness of at least 500 .ANG. across its surface. Its maximum thickness is about 1,000 .ANG. in the specific embodiment due to limits on the effectiveness of the Excimer laser to convert amorphous silicon to polycrystalline silicon (see step 240 below). Of course, it will be recognized that new techniques, processes and materials may be developed that will have different minimum and maximum specifications.
Next, in step 240, first amorphous silicon layer 130 is annealed at high
temperature by applying rapid thermal energy to the region, thereby converting
amorphous silicon layer 130 to transparent polycrystalline silicon layer 135. In
this context, annealing is defined as the process of converting amorphous
silicon to polycrystalline silicon. The resulting structure is depicted in FIG.
6. In the specific embodiment, this annealing is accomplished with a pulsed
Excimer laser, which is a gas laser using xenon chloride. The Excimer laser
heats up the material at approximately 1,000,000 degrees per second allowing
first amorphous silicon layer 130 to be rapidly annealed. Other types of lasers
or other rapid thermal energy devices may also be preferably used to perform
this annealing. For example, a diode laser that has been frequency
converted to ultraviolet frequencies, a diode crystal laser that has been frequency converted to ultraviolet frequencies, and a diode pumped crystal (YAG or YELF) laser that has been frequency converted to ultraviolet frequencies are examples of lasers that may be used, although the present invention is not limited to only these types of lasers.
The Excimer laser outputs a beam that effectively converts amorphous silicon to polycrystalline silicon for a depth of approximately 1,000 .ANG.. Because it heats up only such a relatively short distance into the structure, the underlying substrate is not subjected to the high temperatures to which the amorphous silicon layer is subjected. Therefore, in contrast to other methodologies, the substrate may be of a low melting point material such as plastic. In the specific embodiment, the Excimer laser is operated at 248-308 nm at, typically, 600 mJ/cm.sup.2, with a pulse duration of no more than 50 nanoseconds, but typically 45 nanoseconds.
In applications in which the substrate can be processed at moderately high temperatures (for example, glass at 550 degrees C.,) rapid thermal annealing of amorphous silicon into polycrystalline silicon could alternatively be done using flash lamps or similar devices (e.g. pulsed CO.sub.2 lasers).
This annealing step also serves to activate the p-type dopant. In the specific embodiment, the underlying substrate may be preheated to a temperature below the melting point of the substrate before applying the laser. In the specific embodiment, this preheating is approximately 300 to 350 degrees. Other embodiments may not use any preheating at all.
The amorphous silicon deposition process of step 230 and the thermal annealing process of step 240 results in a particular grain size for polycrystalline silicon layer 135. In the specific embodiment, the root mean square (RMS) of grain sizes is between 0.25 microns and 0.50 microns. The grain size is preferably between 0.1 micron and 2.0 microns.
In step 245, a temporary barrier (not shown) is formed overlying polycrystalline silicon layer 135. This step is optional and may be skipped in some embodiments. The barrier is preferably a 50 .ANG. thick layer of SiO.sub.2, a nitride, or other dielectric material. Its purpose is to seal polycrystalline silicon layer 135 from a subsequent oppositely doped layer. The barrier is intended to be temporary and may be removed in later processing.
In steps 250, second doped amorphous silicon layer 140 is formed overlying
polycrystalline silicon layer 135. Amorphous silicon layer 140 is oppositely
doped from amorphous silicon layer 130. The resulting structure is shown in FIG.
7. In the specific embodiment, amorphous silicon layer 140 is doped with an
n-type material such as phosphene or other n-type dopant. It may be formed with
in-situ doping and CVD deposition. Other embodiments may reverse the order of
the different dopant types in amorphous silicon layers 130 and 140 so that the
p-type layer overlies the n-type layer. Amorphous silicon layer 140 may
alternatively be doped by implantation or diffusion.
In step 260, amorphous silicon layer 140 is annealed using the Excimer laser or other rapid thermal energy process as described in step 240. This results in a transparent polycrystalline silicon layer 145. The resulting structure is shown in FIG. 8. Step 260 also activates the dopant. The barrier formed in step 245 may be removed during the annealing process leaving a P-N junction between layers 135 and 145.
In step 270, a second conductive layer 150 is formed above the P-N junction resulting in solar cell 100 as shown in FIG. 1. In the specific embodiment, the second conductive layer is also ITO that is deposited with CVD at a thickness of about one-half micron over the area of interest. Again, its maximum thickness is dependent upon the desired transparency, conductivity, and flexibility. Second conductive layer 150 may also be optionally annealed to improve the mobility of the electrons and holes.
Steps 220-270 may be performed using a roll-to-roll coater. Such roll-to-roll coaters are well known in the art. Using this technique, large sheets of solar cells 100 may be formed on large rolls of a substrate such as plastic. Processing steps 220-270 are performed with equipment located between the two rolls of the roll-to-roll coater. The Excimer laser is one of these pieces of equipment. It typically outputs a beam that is 0.6 mm wide and extends across the substrate. Multiple lasers may be also be used together to increase the rate of processing over large surface areas. The rolls of plastic may be moved so the entire substrate is exposed to the laser. Alternatively, the laser may be moved over the substrate instead of moving the substrate.
FIG. 9A shows a cross section of solar cell 100 during an embodiment of annealing process of step 240. A sheet of substrate 110 has already been layered with transparent conductor 120 and amorphous silicon 130. A laser 300 resides above the sheet and transmits thermal energy into amorphous silicon 130 converting it to polycrystalline silicon 135 as the sheet moves past laser 300. As described above, laser 300 may be an Excimer laser or other type of laser. The thermal energy output of laser 300 is such that amorphous silicon layer 130 is heated above approximately 1400.degree. C. to convert it to polycrystalline silicon, but substrate 110 remains below 450.degree. C. FIG. 9B shows a thermal graph of the temperature of the sheet through its depth. At the top of amorphous silicon 130, the temperature may be 1450.degree. C. while at the bottom it is approximately 1400.degree. C. Through transparent conductor 120 the temperature declines rapidly until it is less than 450.degree. C. at substrate 110. In the specific embodiment, the laser moves across the sheet slow enough that each pulse of the laser overlaps the portion that was previously exposed to the beam. Preferably the overlap is two thirds the width of the beam. A typical scan rate is 60 mm per second.
In operation, electrodes are provided to each of the p+ and n- polycrystalline silicon layers 135 and 145 to form an electrical circuit. In the presence of optical radiation, the P-N junction of the specific embodiment develops a typical 0.46 volt potential at approximately 7 mA/cm.sup.2 in sunlight. However, it can be constructed such that a wide range of power output is provided. Such outputs can vary by orders of magnitude. The size of the area, the quantum efficiency of the cell (electron-hole mobility/absorptivity) and the energy level of the instant optical energy determines the amount of optical energy converted to electrical current. A typical design efficiency is about 2-3% or better, as compared with an opaque crystalline solar cell with an efficiency of 13%. An advantage of solar cell 100 is that it does not depend on hydrogen as a carrier, so it does not suffer from the efficiency loss that amorphous silicon does. Thus, its lifetime is extended over that of amorphous solar cells.
In another embodiment of the present invention, multiple layers of P-N junctions may be formed by repeating steps 220-270. The resulting multiple layer solar cell may increase the efficiency to more closely resemble that of crystalline solar cells. FIG. 9 is a cross-sectional diagram of a resulting multiple layer solar cell 900. Although solar cell 900 shows only two levels of solar cells, any number may be formed. Since these layers are transparent, the resulting solar cells in the lower levels are exposed to the light even though they are underneath other solar cells. This may be desirable for some applications to increase the efficiency and extend the life of the resulting structure.
Referring to FIG. 10, a single layer solar cell such as solar cell 100 is formed and an additional solar cell is formed above it to form a multiple layer solar cell 900. In some embodiments, second transparent conductor 150 is thicker than first transparent conductor 120. In other embodiments it is the same thickness. In still other embodiments, a dielectric layer (not shown) is formed on another conductive layer (not shown) is formed above the dielectric layer.
A second p+ polycrystalline layer 910 is formed by forming a p+ amorphous silicon layer and annealing it as described above. A second n- polycrystalline layer 910 is formed above second p+ polycrystalline layer 910 by forming an n- amorphous silicon layer and annealing it. A third transparent conductor 930 is formed above that. This process may be repeated to form as many layers as is desirable.
As described briefly above, the reflectivity of solar cell 100 may be varied depending on the application. In some embodiments, it is desirable that the outer conductive layer (i.e., second conductive layer 150) be as anti-reflective as possible, while the inner conductive layer (i.e., first conductive layer 120) is reflective. Such a design will allow the maximum amount of sunlight to be absorbed since it passes through solar cell 100 as it enters and as it is reflected back. Other embodiments may make use of various reflective qualities for functional or aesthetic reasons.
To provide the reflectivity, an embodiment substitutes a flash of silver, aluminum, titanium or other reflective conductor instead of a transparent conductor such as ITO. This substitution can be made on any or all of the conductive layers, depending on the desired reflectivity.
In other embodiments of the present invention, solar cell 100 may also be used as an optical filter. Using the above-described methodology, solar cell 100 provides a photopic response that is very similar to that of the human eye. That is, it absorbs about 20-80% of those light frequencies which are visible to the human eye, while allowing the rest of the visible light to pass through. It can be used as an optical filter alone, or in combination with its use as a solar cell.
While a specific embodiment has been described herein, it will be recognized that the present invention is not limited to the specific embodiment described. For example, the p+ and n- layers 135 and 145 may be reversed. Also, different or new fabrication techniques may be used or other changes made that do not depart from this spirit and scope of the present invention. The invention is intended to be limited only by the attached claims.
United States Patent 6,509,204 Campbell January 21, 2003
Transparent solar cell and method of fabrication
Abstract A device such as a transparent solar cell or optical filter and method of its manufacture. The method includes steps of forming a first conductive layer overlying a substrate. The method also includes forming a first amorphous silicon layer overlying the first conductive layer. A step of annealing the first amorphous silicon layer is included. The annealing step may be performed using a laser. It may also be performed by maintaining the substrate at a temperature of less than 450 degrees Celsius. A second conductive layer may be formed overlying the second amorphous silicon layer.
Inventors: Campbell; James P. (Atherton, CA)
Assignee: Xoptix, Inc. (Woodland Hills, CA)
Appl. No.: 772825
Filed: January 29, 2001
Current U.S. Class: 438/97; 438/96; 438/486; 438/487
Intern'l Class: H01L 021/00; H01L 021/20
Field of Search: 438/48,57,61,62,96,97,149,151,166,486,482 136/258,261
References Cited [Referenced By]
|
U.S. Patent Documents
4059461 Nov., 1977 Fan et al. 148/1.
-------
4214918 Jul., 1980 Gat et al. 148/1.
-------
4400577 Aug., 1983 Spear 136/259.
-------
4642413 Feb., 1987 Ovshinsky.
-------
4663495 May., 1987 Berman et al. 136/248.
-------
4824489 Apr., 1989 Cogan et al. 136/256.
-------
5192991 Mar., 1993 Hosokawa 257/51.
-------
5413959 May., 1995 Yamamoto et al. 437/174.
-------
5667597 Sep., 1997 Ishihara 136/258.
-------
5677240 Oct., 1997 Murakami et al.
-------
5714404 Feb., 1998 Mitlitsky et al.
-------
5886688 Mar., 1999 Fifield et al. 345/206.
-------
6180871 Jan., 2001 Campbell et al.
-------
6320117 Nov., 2001 Campbell et al. 136/258.
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Primary Examiner: Christianson; Keith
Attorney, Agent or Firm: Townsend and Townsend and Crew LLP, Allen; Kenneth R.
Claims
What is claimed is:
1. A method of fabricating a device comprising:
forming a first conductive layer overlying a substrate;
forming a first amorphous silicon layer overlying the first conductive layer; and
annealing the first amorphous silicon layer by applying thermal energy with a laser to convert amorphous silicon of the first amorphous silicon layer into polycrystalline silicon.
2. The method of claim 1 wherein the first amorphous silicon layer is doped with a p+ type dopant.
3. The method of claim 1 further comprising annealing the first conductive layer.
4. The method of claim 1 wherein the annealing of the first amorphous layer is done by applying thermal energy while maintaining the substrate at a temperature of less than 450.degree. C.
5. The method of claim 1 wherein the laser is an Excimer laser.
6. The method of claim 2 wherein the laser is a pulsed Excimer laser.
7. The method of claim 1 wherein the first conductive layer is a semiconductive metal.
8. The method of claim 1 wherein the first conductive layer is Indium Tin Oxide.
9. The method of claim 1 further comprising forming a second conductive layer overlying the polycrystalline silicon.
10. The method of claim 9 further comprising:
forming a second amorphous silicon layer overlying the second conductive layer; and
annealing the second amorphous silicon layer by applying thermal energy with a laser.
11. A solar cell having been formed by the method of claim 1.
12. An optical filter having been formed by the method of claim 1.
13. A method for fabricating a transparent device, the method comprising:
forming a first conductive layer overlying a transparent substrate;
forming a first amorphous silicon layer overlying the first conductive layer; and
converting the first amorphous silicon layer into polycrystalline silicon by application of thermal energy while maintaining the transparent substrate at a temperature of less than 450 degrees Celsius.
14. The method of claim 13 wherein the first conductive layer and the first polycrystalline silicon form a Schottky barrier diode.
15. The method of claim 13 wherein the first polycrystalline silicon layer includes a thickness of 1000 .ANG. and less, which provides a transparent structure.
16. The method of claim 13 further comprising:
forming a second conductive layer overlying the first amorphous silicon layer.
17. The method of claim 16 further comprising:
forming a second amorphous silicon layer overlying the first conductive layer; and
converting the first amorphous silicon layer into polycrystalline silicon by application of thermal energy while maintaining the transparent substrate at a temperature of less than 450 degrees Celsius.
18. The method of claim 13 wherein the converting from the first amorphous silicon layer is provided using a rapid thermal anneal process, the rapid thermal anneal process maintaining a temperature of less than about 450.degree. C. at the transparent substrate.
19. The method of claim 13 wherein the converting from the first amorphous silicon layer is provided using a laser.
Description
BACKGROUND OF THE INVENTION
The present invention relates, in general, to electronic devices. More particularly, the present invention provides a transparent solar cell and optical filter formed with a Schottky barrier diode and method of its manufacture.
Solar energy provides many advantages over traditional energy sources. For example, energy from the sun is virtually unlimited and easily accessible throughout the world. It does not require the extraction of a natural resource from the ground to obtain the energy and it can be converted to electricity in a manner that is not harmful to the environment. Solar energy is available whenever the sun is shining and can be collected and stored for use when no light source is available. Therefore, if it can be harnessed economically, it provides an environmentally friendly source of energy that does not deplete or destroy precious natural resources. This is in stark contrast to the use of fossil fuels that are of limited supply and which cause environmental damage with both their use and extraction processes. The use of fossil fuel also requires a constant source of raw materials that may be difficult to obtain in many circumstances.
Many different applications benefit greatly from the use of solar energy. For example, buildings and automobiles with their broad surfaces that are exposed to the sun's energy for much of the day can use that energy to provide some or all of their energy needs. Various solar cells have been developed using different fabrication techniques to take advantage of this energy source.
The inventor of the present invention has previously filed patent applications directed toward a particularly beneficial solar cell. That patent application describes a structure that includes a p-n junction diode. The p+ and n- polycrystalline silicon structures making up the pin junction are formed using an Excimer laser. An advantage of using the Excimer laser is that it may form the polycrystalline silicon without destroying a low melting point substrate upon which the solar cell is fabricated.
The prior art also includes other types of solar cells with pin junctions. One type of solar cell is formed with crystalline silicon. For these solar cells, crystalline silicon is formed by melting silicon and drawing an ingot of crystalline silicon of the size desired. Alternatively, a ribbon of crystalline silicon can be pulled from molten silicon to form a crystalline silicon solar cell. A conductor is placed on either side of the crystalline silicon to form the solar cell. These processes use high temperatures and the solar cells are expensive to manufacture. Packaging is also difficult and expensive and creates a rigid structure. Their maximum size is limited by the manufacturing process. It is difficult to slice the resulting crystalline silicon thin enough to provide a transparent or flexible solar cell. However, these structures are very efficient (relative to other types of presently available commercial solar cells). As such, crystalline solar cells are used primarily for applications where efficiency is more important than cost and where the structures do not need to be flexible. For example, these are commonly used on satellites.
Another type of solar cell is formed with polycrystalline silicon. These may be formed as thin layers on wafers and can thus be made thinner than crystalline silicon solar cells. As is well known in the art, polycrystalline silicon can be formed by heating amorphous silicon and allowing it to cool. Typically, amorphous silicon begins to crystallize after it melts at temperatures greater than about 1400.degree. C. and begins to cool below that level. Because of these high temperatures, known processes can only use substrates with high melting points. These processes are not appropriate for substrates made of plastics or other materials that melt at lower temperatures. In the manufacture of flat panel displays, it is known to use lasers to form polycrystalline silicon thin film transistors (TFTs). Such use has not included the formation of P-N junctions or solar cells which presents its own set of challenges. Moreover, these manufacturing processes generally formed single transistors and were not used to form large sheets or areas of polycrystalline silicon. Further, lasers have been used in the manufacture of solar cells, but only as a tool to mechanically form (slice, pattern, etch, etc.) the solar cells.
Another type of solar cell has been formed using doped layers of amorphous silicon. These are not subject to some of the problems inherent in the previously described crystalline silicon or polycrystalline solar cells. First, amorphous silicon can be formed using low temperature processes. Thus, it can be formed on plastic and other flexible substrates. They can also be formed over large surfaces. Second, the processing techniques are less expensive. Nevertheless, amorphous solar cells introduce other significant limitations not found in crystalline silicon or polycrystalline silicon solar cells. For example, hydrogen is generally added during the manufacturing to increase the efficiency of the cell. Amorphous silicon solar cells tend however to lose this hydrogen over time, causing reduced efficiency and reduced usable life. Moreover, amorphous silicon solar cells are not transparent. Thus, they are not appropriate for many applications. For example, buildings and cars with solar cells can be unsightly, and the solar panels may block the view of the outdoors or access to outside light indoors. Also, portable electronics often place a premium on size and surface area. Some devices have displays that cover most--if not all--of the exposed surface of the device. Therefore, it is often undesirable or impossible to mount a traditional amorphous silicon solar cell on the device.
Attempts have been made to solve this transparency problem by making transparent panels from existing solar cell processes. One method has been to take advantage of the "window shade effect" whereby solar cells are formed on a transparent substrate with gaps between adjacent solar cells. This allows some light to pass through to create a transparent effect. The larger the gaps, the more transparency the device has. A disadvantage of this technique is that much of the space is unused, therefore the efficiency of the device is less than it would be if all of the surface area was used for solar cells. Of course, devices of this type also suffer from the problems inherent to the type of cell used. For example, if based on amorphous silicon, these devices suffer from the hydrogen loss exhibited in other amorphous silicon devices.
Other work has been done at making transparent solar cells using materials other than silicon (for example, cadmium telluride (CdTe)). These cells suffer from the challenges inherit to using materials other than silicon.
Thus, a new solar cell and method of fabrication that will avoid these problems and is more efficient to manufacture is desirable.
SUMMARY OF THE INVENTION
The present invention provides improved devices such as transparent solar cells and optical filters. It also provides improved methods for forming those devices. In contrast with devices and methods previously disclosed by the present inventor, these improved devices and methods use fewer layers resulting in simpler, less expensive fabrication processes and resulting in simpler devices along with other beneficial results. Moreover, compared with other fabrication techniques, the present invention allows for the fabrication of devices that are transparent using existing fabrication equipment and processing steps, while allowing those processes to be done quickly. In some embodiments, the processes may be completed on low melting point substrates that would be destroyed using previously known techniques.
In a first embodiment of the present invention, a method is provided for fabricating a device. The method comprises forming a first conductive layer overlying a substrate, forming a first amorphous silicon layer overlying the first conductive layer and annealing the first amorphous silicon layer by applying thermal energy with a laser to convert amorphous silicon of the first amorphous silicon layer into polycrystalline silicon. A second conductive layer may be formed overlying the polycrystalline silicon. The methodology produces a Schottky barrier diode between the conductive layer and the polycrystalline silicon. The resulting device may be used as a solar cell or as an optical filter. Steps of the methodology may be repeated to create successive layers of conductors and polycrystalline silicon.
In another embodiment of the present invention, a method is provided for fabricating a transparent device. The method comprises forming a first conductive layer overlying a transparent substrate, forming a first amorphous silicon layer overlying the first conductive layer; and converting the first amorphous silicon layer into polycrystalline silicon by application of thermal energy while maintaining the transparent substrate at a temperature of less than 450.degree. C. An Excimer laser or similar device may be used for applying the thermal energy. Again, a second conductive layer may be formed overlying the polycrystalline silicon and alternating layers of polycrystalline silicon and conductive layers may be formed in subsequent layers.
In yet another embodiment of the present invention, a device that may be used for example as an optical filter or a solar cell is disclosed. The device comprises a substrate with a melting temperature of less than 450.degree. C., a first conductive layer overlying the substrate and a first polycrystalline film formed from a first amorphous silicon layer overlying the first conductive layer. Alternating conductive layers and polycrystalline film layers may be placed above those layers to increase the efficiency of the device.
A further understanding of the nature and advantages of the inventions presented herein may be realized by reference to the remaining portions of the specification and the attached drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cross-sectional diagram of a transparent solar cell according to the present invention;
FIG. 2 is a flow diagram showing a method of fabricating solar cells according to the present invention;
FIGS. 3-6 are cross-sectional diagrams of the solar cell of the present invention at various steps of fabrication;
FIG. 7 shows a cross section of the solar cell during an embodiment of annealing process;
FIG. 8 shows a thermal graph of the solar cell's temperature through its depth during the annealing process; and
FIG. 9 is a cross-sectional diagram of a multiple layer solar cell of the present invention.
DESCRIPTION OF THE SPECIFIC EMBODIMENTS
FIG. 1 is a cross-sectional diagram of an embodiment of a solar cell 100 according to the present invention. While referred to generically herein as a solar cell, solar cell 100 also may operate efficiently as an optical filter. Moreover, it may be used as a solar cell exclusively, an optical filter exclusively, or as a combination solar cell and optical filter.
Solar cell 100 may be fabricated in sheets of a size appropriate for its intended use. It may also be fabricated on small substrates or in configurations other than sheets. For example, solar cell 100 may be fabricated as a small device for a hand-held electronic device or on large sheets to be applied to large areas such as windows, buildings and automobiles. In contrast to most amorphous silicon solar cells, solar cell 100 is transparent. In this context, transparency is defined as having the property of transmitting light without appreciable scattering so that bodies lying beyond are seen clearly. In the specific embodiment, the reflective component is very low; however, the amount of reflection is controllable in the manufacturing process as will be discussed in more detail below.
Solar cell 100 has a substrate layer 110 providing a base structure for the
device. Substrate layer 110 may be a flexible material or a rigid material
depending on its intended use. A first conductive layer 120 overlies substrate
110. A transparent polycrystalline silicon layer 135 overlies first conductive
layer 120. An intrinsic layer 138 exists at the junction between polycrystalline
silicon layer 135 and transparent conductor 120. Intrinsic layer 138 forms a
Schottky barrier diode between the two layers. Polycrystalline silicon layer 135
may obtain its transparency by virtue of its method of fabrication as will be
described in detail below. A second conductive layer 150 resides above
polycrystalline silicon layer 135 and the junction between conductive layer 150
and polycrystalline silicon layer 135 forms another Schottky barrier diode.
Because of its transparent nature, solar cell 100 can be placed unobtrusively over a variety of surfaces to gather light energy and convert the light energy to electricity. For example, it can be used as window covering on buildings or automobiles while maintaining the aesthetics and functionality of the window. Such a window covering can absorb some of the photons from sunlight or other light sources to produce electricity, while allowing those photons not absorbed to pass through to the other side. Thus, the view through the covered window is not completely blocked. Similarly, solar cell 100 can cover a display from a laptop computer or other electronic device such that it can gather light and generate electricity whether the device is in operation or not. Such electronic devices may include portable telephones, laptop computers, palm top computers, electronic watches, etc. While this is a list of some of its applications, it is of course not exhaustive. One can readily identify many applications in which transparent solar cell 100 might be used to generate electricity while not obscuring in any significant degree, the view of the user.
In another embodiment of the present invention, solar cell 100 may operate effectively as an optical filter. In yet another embodiment, it may operate as both a solar cell and an optical filter. As an optical filter, it filters out light in undesirable frequencies, while allowing light in the visible frequencies to pass through. Because of its low reflectivity, it may also be used in applications that benefit from anti-reflective coatings. While it is referred to herein generically as solar cell 100, it is specifically intended that the term include its usage as an optical filter as well.
FIG. 2 shows a flow diagram of a method of fabricating solar cell 100 according to the present invention. While FIG. 2 shows a specific embodiment, it is not intended that this be the only way such a transparent solar cell may be fabricated. One of skill in the art will recognize that other variations of the invention are readily apparent from the specific embodiment described herein.
Referring to the flow diagram of FIG. 2, in step 210 a suitable substrate 110 is provided upon which solar cell 100 may be fabricated. FIG. 3 shows a cross-section of the device at step 210 of the fabrication. Substrate 110 may be a rigid or flexible material. For example, flexible substrates such as plastic, Mylar or Polyolifin may be used. Rigid substrates such as glass, crystal, acrylic, or ceramic may also be used. Substrate 110 need not be a material with a high melting point compared to the temperature at which amorphous silicon crystallizes. Instead, it may include plastics and other materials that have relatively low melting temperatures. This is in stark contrast to previously known crystalline solar cells that required the use of a substrate of a high melting point to withstand the fabrication process. One of skill in the art will recognize many acceptable materials for substrate 110 and any may be used without departing from the present invention. The selection of a rigid or flexible substrate 110 is arbitrary except to the extent that a rigid or flexible structure is more appropriate for the end use of solar cell 100. Depending upon the embodiment, substrate 110 may also be coated with a variety of materials. The substrate can also be dyed.
In step 220, a first conductive layer 120 is formed on substrate 110 as depicted in FIG. 4. Conductive layer 120 may be a semiconductive metal. In the specific embodiment, conductive layer 120 is indium tin oxide (ITO) that is deposited by chemical vapor deposition (CVD). Tin Oxide may also be used as the semiconductive metal. In an embodiment of the present invention, a flash of silver, aluminum, titanium or other reflective coating may be used to provide a more reflective solar cell. The specific embodiment has an ITO thickness of approximately one half micron over the area of interest; however, other dimensions may be appropriate for different applications and materials. Its thickness is a function of the desired amount of transparency, conductivity, and flexibility. It may be desirable for conductive layer 120 to be annealed after it has been deposited. Such annealing improves mobility of electrons and holes in conductive layer 120. Conductive layer 120 may also be deposited or formed in other ways besides CVD. First conductive layer 120 may be a single layer or multiple layers, depending upon the embodiment.
In step 225, first conductive layer 120 is optionally cleaned using any of a variety of techniques well known in the art. Such techniques include metal etching, laser scan, etc.
In step 230, a first doped amorphous silicon layer 130 is formed overlying the region of interest of conductive layer 120. The resulting structure is shown in FIG. 5. In the specific embodiment, amorphous silicon layer 130 is a p+ type material. It is in-situ doped using CVD with boron at concentration levels such as are commonly used for producing solar cells. In other embodiments, amorphous silicon layer 130 may be formed by implantation or diffusion processes. First amorphous silicon layer 130 preferably has a thickness of at least 300 .ANG. at its thinnest points and a nominal thickness of at least 500 .ANG. across its surface. Its maximum thickness is about 1,000 .ANG. in the specific embodiment due to limits on the effectiveness of the Excimer laser to convert amorphous silicon to polycrystalline silicon (see step 240 below). Of course, it will be recognized that new techniques, processes and materials may be developed that will have different minimum and maximum specifications.
Next, in step 240, first amorphous silicon layer 130 is annealed at high temperature by applying rapid thermal energy to the region, thereby converting amorphous silicon layer 130 to transparent polycrystalline silicon layer 135. When the material is converted to polycrystalline silicon, intrisic region 138 forms between amorphous silicon layer 130 and polycrystalline silicon layer 135 forming a Schottky barrier diode.
In this context, annealing is defined as the process of converting amorphous
silicon to polycrystalline silicon. The resulting structure is depicted in FIG.
6. In the specific embodiment, this annealing is accomplished with a pulsed
Excimer laser, which is a gas laser using xenon chloride. The Excimer laser
heats up the material at approximately 1,000,000 degrees per second allowing
first amorphous silicon layer 130 to be rapidly annealed. Other types of lasers
or other rapid thermal energy devices may also be preferably used to perform
this annealing. For example, a diode laser that has been frequency converted to
ultraviolet frequencies, a diode crystal laser that has been frequency converted
to ultraviolet frequencies, and a diode pumped crystal (YAG or YELF) laser that
has been frequency converted to ultraviolet frequencies are examples of lasers
that may be used, although the present invention is not limited to only these
types of lasers.
The Excimer laser outputs a beam that effectively converts amorphous silicon to polycrystalline silicon for a depth of approximately 1,000 .ANG.. Because the Excimer laser only heats the structure for such a relatively short distance into the structure, the underlying substrate is not subjected to the high temperatures to which the amorphous silicon layer 130 is subjected. Therefore, in contrast to other methodologies of fabrication, the substrate may formed of a low melting point material such as plastic. In the specific embodiment, the Excimer laser is operated at 248-308 nm at, typically, 600 mJ/cm.sup.2, with a pulse duration of no more than 50 nanoseconds, but typically 45 nanoseconds.
In applications in which the substrate can be processed at moderately high temperatures (for example, glass at 550 degrees C.,) rapid thermal annealing of amorphous silicon into polycrystalline silicon could alternatively be done using flash lamps or similar devices (e.g. pulsed CO.sub.2 lasers).
This annealing step also serves to activate the dopant. In the specific embodiment, the underlying substrate may be preheated to a temperature below the melting point of the substrate before applying the laser. In the specific embodiment, the substrate is preheated to approximately 300 to 350 degrees. Other embodiments may not use any preheating at all.
The amorphous silicon deposition process of step 230 and the thermal annealing process of step 240 result in a particular grain size for polycrystalline silicon layer 135. In the specific embodiment, the root mean square (RMS) of grain sizes is between 0.25 microns and 0.50 microns. The grain size is preferably between 0.1 micron and 2.0 microns.
In step 245, a temporary barrier (not shown) is formed overlying polycrystalline silicon layer 135. This step is optional and may be skipped in some embodiments. The barrier is preferably a 50 .ANG. thick layer of SiO.sub.2, a nitride, or other dielectric material. Its purpose is to seal polycrystalline silicon layer 135 from a subsequent layer. The barrier is intended to be temporary and may be removed in later processing.
In step 270, a second conductive layer 150 is formed above the polycrystalline
silicon layer 135 resulting in solar cell 100 as shown in FIG. 1. Second
conductive layer 150 may a semiconductive metal such as Indium Tin Oxide or Tin
Oxide. It could also be any other conductive substance. An advantage of using a
semiconductive metal is that it provides a second intrinsic layer.
Alternatively, first conductive layer 120 may be a non-semiconductive metal and
second conductive layer 120 is a semiconductive metal. In the specific
embodiment, the second conductive layer is also ITO that is deposited with CVD
at a thickness ranging from about one-half micron to three microns over the area
of interest. Again, its maximum thickness is dependent upon the desired
transparency, conductivity, and flexibility. Second conductive layer 150 may
also be optionally annealed to improve the mobility of the electrons and holes.
Steps 220-270 may be performed using a roll-to-roll coater. Such roll-to-roll coaters are well known in the art. Using this technique, large sheets of solar cells 100 may be formed on large rolls of a substrate such as plastic. Processing steps 220-270 is performed with equipment located between the two rolls of the roll-to-roll coater. The Excimer laser is one of these pieces of equipment. It typically outputs a beam that is 0.6 mm wide and extends across the substrate. Multiple lasers may also be used together to increase the rate of processing over large surface areas. The rolls of plastic may be moved so the entire substrate is exposed to the laser. Alternatively, the laser may be moved over the substrate instead of moving the substrate. Moreover, rather than being formed on large rolls, the materials may be deposited directly on a substrate such as glass and exposed to the Excimer laser. Convention glass manufacturing processes may be adapted to include the Excimer laser.
FIG. 7 shows a cross section of solar cell 100 during an embodiment of the annealing process of step 240. A sheet of substrate 110 has already been layered with transparent conductor 120 and amorphous silicon 130. A laser 300 resides above the sheet and transmits thermal energy into amorphous silicon 130 converting it to polycrystalline silicon 135 as the sheet moves past laser 300. As described above, laser 300 may be an Excimer laser or other type of laser. The thermal energy output of laser 300 is such that amorphous silicon layer 130 is heated above approximately 1410.degree. C. (the melting point of Silicon) to convert it to polycrystalline silicon, but substrate 110 remains below 450.degree. C.
FIG. 8 shows a thermal graph of the temperature of the sheet through its depth. At the top of amorphous silicon 130, the temperature may be 1450.degree. C. while at the bottom it is approximately 1400.degree. C. Through transparent conductor 120 the temperature declines rapidly until it is less than 450.degree. C. at substrate 110. In the specific embodiment, the laser moves across the sheet slow enough that each pulse of the laser overlaps the portion that was previously exposed to the beam. Preferably the overlap is two-thirds the width of the beam. A typical scan rate is 60 mm per second.
In operation, an electrode is provided to the polycrystalline silicon layer 135 and one or more of the transparent conductor layers 120 and 150 to form an electrical circuit. In the presence of optical radiation, the Schottky barrier diodes between the polycrystalline layers and the conductive layers of the specific embodiment develops a typical 0.46 volt potential at approximately 7 mA/cm.sup.2 in sunlight. However, it can be constructed such that a wide range of power output is provided. Such outputs can vary by orders of magnitude. The size of the area, the quantum efficiency of the cell (electron-hole mobility/absorptivity) and the energy level of the instant optical energy determine the amount of optical energy converted to electrical current. A typical design efficiency is about 2-3% or better, as compared with an opaque crystalline solar cell with an efficiency of 13%. An advantage of solar cell 100 is that it does not depend on hydrogen as a carrier, so it does not suffer from the efficiency loss that amorphous silicon does. Thus, its lifetime is extended over that of amorphous solar cells.
In another embodiment of the present invention, multiple layers of P-N junctions may be formed by repeating steps 220-270. The resulting multiple layer solar cell may increase the efficiency to more closely resemble that of crystalline solar cells. FIG. 9 is a cross-sectional diagram of a resulting multiple layer solar cell 900. Although solar cell 900 shows three levels of solar cells, any number may be formed. Since these layers are transparent, the resulting solar cells in the lower levels are exposed to the light even though they are underneath other solar cells. This may be desirable for some applications to increase the efficiency and extend the life of the resulting structure.
Referring to FIG. 9, a single layer solar cell such as solar cell 100 is formed and an additional solar cell is formed above it to form a multiple layer solar cell 900. In some embodiments, second transparent conductor 150 is thicker than first transparent conductor 120. In other embodiments it is the same thickness. In still other embodiments, a dielectric layer (not shown) is formed on another conductive layer (not shown).
A second polycrystalline layer 910 is formed by forming an amorphous silicon layer and annealing it as described above. A third transparent conductor 920 is formed above that. This process may be repeated to form as many layers as is desirable such as shown with a third polycrystalline silicon layer 925 and fourth transparent conductor layer 930.
As described briefly above, the reflectivity of solar cell 100 may be varied depending on the application. In some embodiments, it is desirable that the outer conductive layer (i.e., second conductive layer 150) be as anti-reflective as possible, while the inner conductive layer (i.e., first conductive layer 120) is reflective. Such a design will allow the maximum amount of sunlight to be absorbed since it passes through solar cell 100 as it enters and as it is reflected back. Other embodiments may make use of various reflective qualities for functional or aesthetic reasons.
To provide the reflectivity, an embodiment substitutes a flash of silver, aluminum, titanium or other reflective conductor instead of a transparent conductor such as ITO. This substitution can be made on any or all of the conductive layers, depending on the desired reflectivity.
In other embodiments of the present invention, solar cell 100 may also be used as an optical filter. Using the above-described methodology, solar cell 100 provides a photopic response that is very similar to that of the human eye. That is, it absorbs about 20-80% of those light frequencies which are visible to the human eye, while allowing the rest of the visible light to pass through. It can be used as an optical filter alone, or in combination with its use as a solar cell.
While a specific embodiment has been described herein, it will be recognized that the present invention is not limited to the specific embodiment described. For example, different or new fabrication techniques may be used or other changes made that do not depart from this spirit and scope of the present invention. The invention is intended to be limited only by the attached claims.
United States Patent 6,180,871 Campbell , et al. January 30, 2001
Transparent solar cell and method of fabrication
Abstract
A transparent solar cell and method of manufacture. The method includes steps of providing a transparent substrate. The method also includes forming a first conductive layer overlying the substrate. The method also includes forming a first amorphous silicon layer of a first dopant type overlying the first conductive layer. A step of annealing the first amorphous silicon layer is included. The method also forms a second amorphous silicon layer of a second dopant type, and also anneals the second amorphous silicon layer. A second conductive layer is formed overlying the second amorphous silicon layer. A combination of these steps forms a transparent solar cell structure.
Inventors: Campbell; James P. (Atherton, CA); Galyean; Eric W.
(Los Altos Hills, CA); Spreckman; Harvey R. (Thousand Oaks, CA)
Assignee: Xoptix, Inc. (Woodland Hills, CA)
Appl. No.: 343069
Filed: June 29, 1999
Current U.S. Class: 136/258; 136/245; 136/261; 257/74; 257/75; 257/461; 438/96;
438/97
Intern'l Class: H01L 031/109; H01L 031/045
Field of Search: 136/258 PC,258 AM,245,261 257/74,75,461 438/97,96
References Cited [Referenced By]
U.S. Patent Documents
|
4059461 Nov., 1977 Fan et al. 438/92. ------- 4214918 Jul., 1980 Gat et al. 438/618. ------- 4400577 Aug., 1983 Spear 136/259. ------- 4663495 May., 1987 Berman et al. 136/248. ------- 4824489 Apr., 1989 Cogan et al. 136/256. ------- 5192991 Mar., 1993 Hosokawa 136/258. ------- 5413959 May., 1995 Yamamoto et al. 437/174. ------- 5667597 Sep., 1997 Ishihara 136/258. ------- 5886688 Mar., 1999 Fifield et al. 345/206. ------- Primary Examiner: Diamond; Alan Attorney, Agent or Firm: Townsend and Townsend and Crew LLP |
Claims
What is claimed is:
1. A solar cell having been formed by the method of
providing a substrate with a melting temperature of less than 450.degree. C.;
forming a first conductive layer overlying the substrate;
forming a first amorphous silicon layer of a first dopant type overlying the first conductive layer;
annealing the first amorphous silicon layer to convert amorphous silicon of the first amorphous silicon layer into polycrystalline silicon;
forming a second amorphous silicon layer of a second dopant type overlying the first amorphous silicon layer;
annealing the second amorphous silicon layer to convert amorphous silicon of the second amorphous silicon layer into polycrystalline silicon; and
forming a second conductive layer overlying the second amorphous silicon layer.
2. The solar cell of claim 1 wherein the annealing of the first amorphous silicon layer is done by applying thermal energy while maintaining the substrate at a temperature of less then 450.degree. C.
3. The solar cell of claim 1 wherein the annealing of the first amorphous silicon layer comprises application of thermal energy with a laser.
4. The solar cell of claim 3 wherein the laser is a pulsed Excimer laser.
5. The solar cell of claim 1 wherein the solar cell is transparent.
6. A solar cell structure comprising:
a transparent substrate with a melting temperature of less than 450.degree. C.;
a first conductive layer overlying the transparent substrate;
a first polycrystalline film formed from a first amorphous silicon layer of a first dopant type overlying the first conductive layer;
a second polycrystalline film formed from a second amorphous silicon layer of a second dopant type overlying the first amorphous silicon layer; and
a second conductive layer overlying the second polycrystalline film.
7. The solar cell structure of claim 6 wherein the first conductive layer comprises ITO.
8. The solar cell structure of claim 6 wherein the second conductive layer comprises ITO.
9. The solar cell structure of claim 6 wherein the first dopant type is an p+ type impurity.
10. The solar cell structure of claim 6 wherein the second dopant type is a n- type impurity.
11. The solar cell structure of claim 6 wherein the substrate is flexible.
12. A solar cell structure comprising:
a substrate with a melting temperature of less than 450.degree. C.;
a first conductive layer overlying the substrate;
a first polycrystalline film overlying the first conductive layer;
a second polycrystalline film overlying the first polycrystalline film; and
a second conductive layer overlying the second polycrystalline film.
13. The solar cell structure of claim 12 wherein the first polycrystalline film is formed from a first amorphous silicon layer of a first dopant type.
14. The solar cell structure of claim 13 wherein the second polycrystalline film is formed from a second amorphous silicon layer of a second dopant type.
15. The solar cell structure of claim 12 wherein the substrate is transparent.
16. The solar cell structure of claim 12 wherein the first conductive layer is transparent.
17. The solar cell structure of claim 12 wherein the substrate is flexible.
18. The solar cell structure of claim 12 wherein the second polycrystalline film directly overlies the first polycrystalline film with no intervening layer.
Description
BACKGROUND OF THE INVENTION
The present invention relates, in general, to electronic devices. More particularly, the present invention provides a transparent solar cell and method of its manufacture.
Solar energy provides many advantages over traditional energy sources. For example, energy from the sun is virtually unlimited and easily accessible throughout the world. It does not require the extraction of a natural resource from the ground to obtain the energy and it can be converted to electricity in a manner that is not harmful to the environment. Solar energy is available whenever the sun is shining and can be collected and stored for use when no light source is available. Therefore, if it can be harnessed economically, it provides an environmentally friendly source of energy that does not deplete or destroy precious natural resources. This is in stark contrast to the use of fossil fuels that are of limited supply and which cause environmental damage with both their use and extraction processes. The use of fossil fuel also requires a constant source of raw materials that may be difficult obtain in many circumstances.
Many different applications benefit greatly from the use of solar energy. For example, buildings and automobiles, with their broad surfaces that are exposed to the sun's energy for much of the day, can use that energy to provide some or all of their energy needs. Various solar cells have been developed using different fabrication techniques to take advantage of this energy source.
One type of solar cell is formed with crystalline silicon. For these solar cells, crystalline silicon is formed by melting silicon and drawing an ingot of crystalline silicon of the size desired. Alternatively, a ribbon of crystalline silicon can be pulled from molton silicon to form a crystalline silicon solar cell. A conductor is placed on either side of the crystalline silicon to form the solar cell. These processes use high temperatures and the solar cells are expensive to manufacture. Packaging is also difficult and expensive and creates a rigid structure. Their maximum size is limited by the manufacturing process. It is difficult to slice the resulting crystalline silicon thin enough to provide a transparent or flexible solar cell. However, these structures are very efficient (relative to other types of presently available commercial solar cells). As such, crystalline solar cells are used primarily for applications where efficiency is more important than cost and where the structures do not need to be flexible. For example, these are commonly used on satellites.
Another type of solar cell is formed with polycrystalline silicon. These may be formed as thin layers on wafers and can thus be made thinner than crystalline silicon solar cells. As is well known in the art, polycrystalline silicon can be formed by heating amorphous silicon. Typically, amorphous silicon begins to crystallize at temperatures greater than about 1400.degree. C. Because of these high temperatures, known processes can only use substrates with high melting points. These processes are not appropriate for substrates made of plastics or other materials that melt at lower temperatures. In the manufacture of flat panel displays, it is known to use lasers to form polycrystalline silicon thin film transistors (TFTs). Such use has not included the formation of P-N junctions or solar cells which presents its own set of challenges. Moreover, these manufacturing processes generally formed single transistors and were not used to form large sheets or areas of polycrystalline silicon. Further, lasers have been used in the manufacture of solar cells, but only as a tool to mechanically form (slice, pattern, etch, etc.) the solar cells.
Another type of solar cell has been formed using doped layers of amorphous silicon. These are not subject to some of the problems inherent in the previously described crystalline silicon or polycrystalline solar cells. First, amorphous silicon can be formed using low temperature processes. Thus, it can be formed on plastic and other flexible substrates. They can also be formed over large surfaces. Second, the processing techniques are less expensive. Nevertheless, amorphous solar cells introduce other significant limitations not found in crystalline silicon or polycrystalline silicon solar cells. For example, hydrogen is generally added during the manufacturing to increase the efficiency of the cell. Amorphous silicon solar cells tend however to lose this hydrogen over time, causing reduced efficiency and reduced usable life. Moreover, amorphous silicon solar cells are not transparent. Thus, they are not appropriate for many applications. For example, buildings and cars with solar cells can be unsightly, and the solar panels may block the view of the outdoors or access to outside light indoors. Also, portable electronics often place a premium on size and surface area. Some devices have displays that cover most--if not all--of the exposed surface of the device. Therefore, it is often undesirable or impossible to mount a traditional amorphous silicon solar cell on the device.
Attempts have been made to solve this transparency problem by making transparent panels from existing solar cell processes. One method has been to take advantage of the "window shade effect" whereby solar cells are formed on a transparent substrate with gaps between adjacent solar cells. This allows some light to pass through to create a transparent effect. The larger the gaps, the more transparency the device has. A disadvantage of this technique is that much of the space is unused, therefore the efficiency of the device is less than it would be if all of the surface area were used for solar cells. Of course, devices of this type also suffer from the problems inherent to the type of cell used. For example, if based on amorphous silicon, these devices suffer from the hydrogen loss exhibited in other amorphous silicon devices.
Other work has been done at making transparent solar cells using materials other than silicon (for example, cadmium telluride (CdTe)). These cells suffer from the challenges inherit to using materials other than silicon.
Thus, a new solar cell and method of fabrication that will avoid these problems is desirable.
SUMMARY OF THE INVENTION
The present invention provides a solar cell and method of its manufacture. It combines the following advantages: 1) is transparent and therefore can be used in places not applicable to existing solar cells 2) is cost effective because it uses thin film amorphous silicon 3) may be readily manufactured because the method for manufacture uses commercially available CVD and laser annealing equipment and 4) can be used on a wide variety of substrates including low temperature substrates.
According to the present invention, a technique including a method and device for fabricating a solar cell is provided. In an exemplary embodiment, the present invention provides a method and structure which forms a substantially transparent solar cell. The solar cell is thin, flexible, and easy to make and use with conventional semiconductor processes. The solar cell also operates effectively as an optical filter.
In a specific embodiment, the present invention includes a method of forming a solar cell. The method includes steps of providing a substrate, e.g., glass, plastic, Mylar and other substrates, including those with low melting points. The method also includes forming a first conductive layer overlying the substrate. The method also includes forming a first amorphous silicon layer of a first dopant type overlying the first conductive layer. A step of annealing the first amorphous silicon layer is included. The method also forms a second amorphous silicon layer of a second dopant type, and also anneals the second amorphous silicon layer. A second conductive layer is formed overlying the second amorphous silicon layer. A combination of these steps forms a transparent solar cell structure.
In an alternative aspect, the present invention provides a solar cell structure, which is transparent. The structure includes a transparent substrate, which can be selected from glass, crystal, plastic, Mylar, and other substrates, including those that have low melting points. A conductive layer is formed overlying the transparent substrate. A first polycrystalline silicon layer from a first amorphous silicon layer of a first dopant type is formed overlying the first conductive layer. The structure also includes a second polycrystalline silicon layer from a second amorphous silicon layer of a second dopant type overlying the first polycrystalline silicon layer, and a second conductive layer overlying the second polycrystalline silicon layer. The combination of these layers forms a transparent structure.
In a further aspect, the present invention provides a method for fabricating a structure comprising a transparent solar cell structure. The method includes forming a first conductive layer overlying a transparent substrate, and forming a first amorphous silicon layer overlying the first conductive layer. The method also includes converting the first amorphous silicon layer into a first polycrystalline silicon; and forming a second amorphous silicon layer overlying the first amorphous silicon layer. A step of converting the second amorphous silicon layer into a second polycrystalline silicon is included. The method also includes forming a second conductive layer overlying the second amorphous silicon layer. The combination of these steps forms a transparent solar cell structure overlying the substrate.
In still a further aspect, the present invention provides a solar cell comprising a substrate with a melting temperature of less than 450.degree. C., a first conductive layer overlying the substrate, a first polycrystalline film overlying the first conductive layer, a second polycrystalline film overlying the first polycrystalline film, and a second conductive layer overlying the second polycrystalline film.
Numerous advantages are achieved over conventional techniques for forming solar cells. For example, the present method uses conventional equipment and processes from semiconductor operations to manufacture the solar cells. In one aspect of the present invention, an Excimer laser is used to anneal the amorphous silicon layers. Use of this--or a similar laser--allows the forming of polycrystalline silicon without exposing the substrate to high temperature that will distort or destroy it. Therefore, low melting point materials such as plastic may be used. The present solar cells can be transparent, which makes them desirable for placing over glass and other see-through structures. In other aspects, the present invention is easy to implement and control. The present cell structure is extremely thin and efficient and can be implemented on a variety of applications. For example, it can be formed on a flexible substrate and substantially maintain the flexibility of the substrate. Depending upon the embodiment, one or more of these advantages may exist. Other advantages may also exist depending upon the embodiment.
A further understanding of the nature and advantages of the inventions presented herein may be realized by reference to the remaining portions of the specification and the attached drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cross-sectional diagram of a transparent solar cell according to the present invention;
FIG. 2 is a flow diagram showing a method of fabricating solar cells according to the present invention;
FIGS. 3-8 are cross-sectional diagrams of the solar cell of the present
invention at various steps of fabrication; FIG. 9A shows a cross section of the solar cell during an embodiment of annealing process; FIG. 9B shows a thermal graph of the solar cell's temperature through its depth during the annealing process; and FIG. 10 is a cross-sectional diagram of a multiple layer solar cell of the present invention. |
DESCRIPTION OF THE SPECIFIC EMBODIMENTS
FIG. 1 is a cross-sectional diagram of an embodiment of a solar cell 100 according to the present invention. While referred to generically herein as a solar cell, solar cell 100 also may operate efficiently as an optical filter. It may be used as a solar cell exclusively, an optical filter exclusively, or as a combination solar cell and optical filter.
Solar cell 100 may be fabricated in sheets of a size appropriate for its intended use. It may also be fabricated on small substrates or in configurations other than sheets. For example, solar cell 100 may be fabricated as a small device for a hand-held electronic device or on large sheets to be applied to large areas such as windows, buildings and automobiles. In contrast to existing amorphous silicon solar cells, solar cell 100 is transparent. In this context, transparency is defined as having the property of transmitting light without appreciable scattering so that bodies lying beyond are seen clearly. In the specific embodiment, the reflective component is very low; however, the amount of reflection is controllable as will be discussed in more detail below.
Solar cell 100 has a substrate layer 110 providing a base structure for the
device. Substrate layer 110 may be a flexible material or a rigid material
depending on its intended use. A first conductive layer 120 overlies substrate
110. A P-N junction overlies first conductive layer 120. The P-N junction is
formed by a p+ doped transparent polycrystalline silicon layer 135 and an n-
doped transparent polycrystalline silicon layer 145. In other embodiments (not
shown), the order is reversed and p+ polycrystalline silicon layer 135 is formed
above n- polycrystalline layer 145. The p+ doped polycrystalline silicon layer
135 and the n- doped polycrystalline silicon layer 145 may obtain their
transparency by virtue of their method of fabrication as will be described in
detail below. A second conductive layer 150 resides above the P-N junction.
Because of its transparent nature, solar cell 100 can be placed unobtrusively over a variety of surfaces for generating electricity. For example, it can be used as window covering on buildings or automobiles, while maintaining the aesthetics and functionality of the window. Such a window covering can absorb some of the photons from sunlight or other light sources to produce electricity, while allowing those photons not absorbed to pass through to the other side. Thus, the view through the covered window is not completely blocked. Similarly, solar cell 100 can cover a display from a laptop computer or other electronic device such that it can gather light and generate electricity whether the device is in operation or not. Such electronic devices may include portable telephones, laptop computers, palm top computers, electronic watches, etc. While this is a list of some of its applications, it is of course not exhaustive. One can readily identify many applications in which transparent solar cell 100 might be used to generate electricity while not obscuring in any significant degree, the view of the user.
In another embodiment of the present invention, solar cell 100 may operate effectively as an optical filter. In yet another embodiment, it may operate as both a solar cell and an optical filter. It filters out light in undesirable frequencies, while allowing light in the visible frequencies to pass through. Because of its low reflectivity, it may also be used in applications that benefit from anti-reflective coatings. While it is referred to herein generically as solar cell 100, it is specifically intended that the term include its usage as an optical filter as well.
FIG. 2 shows a flow diagram of a method of fabricating solar cell 100 according to the present invention. While FIG. 2 shows a specific embodiment, it is not intended that this be the only way such a transparent solar cell may be fabricated. One of skill in the art will recognize that other variations of the invention are readily apparent from the specific embodiment described herein.
Referring to the flow diagram of FIG. 2, in step 210 a suitable substrate 110 is provided upon which solar cell 100 may be fabricated. FIG. 3 shows a cross-section of the device at step 210 of the fabrication. Substrate 110 may be a rigid or flexible material. For example, flexible substrates such as plastic, Mylar or Polyolifin may be used. Rigid substrates such as glass, crystal, acrylic, or ceramic may also be used. Significantly, substrate 110 need not be a
material with a high melting point compared to the temperature at which amorphous silicon crystallizes. Instead, it may include plastics and other materials that have relatively low melting temperatures. This is in stark contrast to previously known crystalline solar cells that required the use of a substrate of a high melting point to withstand the fabrication process. One of skill in the art will recognize many acceptable material for substrate 110 and any may be used without departing from the present invention. The selection of a rigid or flexible substrate 110 is arbitrary except to the extent that a rigid or flexible structure is more appropriate for the end use of solar cell 100. Depending upon the embodiment, substrate 110 may also be coated with a variety of materials. The substrate can also be dyed.
In step 220, a first conductive layer 120 is formed on substrate 110 as depicted in FIG. 4. In the specific embodiment, conductive layer 120 is indium tin oxide (ITO) that is deposited by chemical vapor deposition (CVD). Other materials for conductive layer 120 include magnesium fluoride, aluminum, tungsten, titanium nitride, gold, silver, etc. In an embodiment of the present invention, a flash of silver, aluminum, titanium or other reflective coating may be used to provide a more reflective solar cell. The specific embodiment has an ITO thickness of approximately one half micron over the area of interest; however, other thicknesses may be appropriate for different applications and materials. Its thickness is a function of the desired amount of transparency, conductivity, and flexibility. It may be desirable for conductive layer 120 to be annealed after it has been deposited. Such annealing improves mobility of electrons and holes in conductive layer 120. Conductive layer 120 may also be deposited or formed in other ways besides CVD. First conductive layer 120 may be a single layer or multiple layers, depending upon the embodiment.
In step 225, first conductive layer 120 is optionally cleaned using any of a variety of techniques well known in the art. Such techniques include metal etching, laser scan, etc.
In step 230, a first doped amorphous silicon layer 130 is formed overlying the region of interest of conductive layer 120. The resulting structure is shown in FIG. 5. In the specific embodiment, amorphous silicon layer 130 is a p+ type material. It is in-situ doped using CVD with boron at concentration such as are commonly used for producing solar cells. In other embodiments, amorphous silicon layer 130 may be formed by implantation or diffusion processes. First amorphous silicon layer 130 preferably has a thickness of at least 300 .ANG. at its thinnest points and a nominal thickness of at least 500 .ANG. across its surface. Its maximum thickness is about 1,000 .ANG. in the specific embodiment due to limits on the effectiveness of the Excimer laser to convert amorphous silicon to polycrystalline silicon (see step 240 below). Of course, it will be recognized that new techniques, processes and materials may be developed that will have different minimum and maximum specifications.
Next, in step 240, first amorphous silicon layer 130 is annealed at high
temperature by applying rapid thermal energy to the region, thereby converting
amorphous silicon layer 130 to transparent polycrystalline silicon layer 135. In
this context, annealing is defined as the process of converting amorphous
silicon to polycrystalline silicon. The resulting structure is depicted in FIG.
6. In the specific embodiment, this annealing is accomplished with a pulsed
Excimer laser, which is a gas laser using xenon chloride. The Excimer laser
heats up the material at approximately 1,000,000 degrees per second allowing
first amorphous silicon layer 130 to be rapidly annealed. Other types of lasers
or other rapid thermal energy devices may also be preferably used to perform
this annealing. For example, a diode laser that has been frequency converted to
ultraviolet frequencies, a diode crystal laser that has been frequency converted
to ultraviolet frequencies, and a diode pumped crystal (YAG or YELF) laser that
has been frequency converted to ultraviolet frequencies are examples of lasers
that may be used, although the present invention is not limited to only these
types of lasers.
The Excimer laser outputs a beam that effectively converts amorphous silicon to polycrystalline silicon for a depth of approximately 1,000 .ANG.. Because it heats up only such a relatively short distance into the structure, the underlying substrate is not subjected to the high temperatures to which the amorphous silicon layer is subjected. Therefore, in contrast to other methodologies, the substrate may be of a low melting point material such as plastic. In the specific embodiment, the Excimer laser is operated at 248-308 nm at, typically, 600 mJ/cm.sup.2, with a pulse duration of no more than 50 nanoseconds, but typically 45 nanoseconds.
In applications in which the substrate can be processed at moderately high temperatures (for example, glass at 550 degrees C.) rapid thermal annealing of amorphous silicon into polycrystalline silicon could alternatively be done using flash lamps or similar devices (e.g. pulsed CO.sub.2 lasers).
This annealing step also serves to activate the p-type dopant. In the specific embodiment, the underlying substrate may be preheated to a temperature below the melting point of the substrate before applying the laser. In the specific embodiment, this preheating is approximately 300 to 350 degrees. Other embodiments may not use any preheating at all.
The amorphous silicon deposition process of step 230 and the thermal annealing process of step 240 results in a particular grain size for polycrystalline silicon layer 135. In the specific embodiment, the root mean square (RMS) of grain sizes is between 0.25 microns and 0.50 microns. The grain size is preferably between 0.1 micron and 2.0 microns.
In step 245, a temporary barrier (not shown) is formed overlying polycrystalline silicon layer 135. This step is optional and may be skipped in some embodiments. The barrier is preferably a 50 .ANG. thick layer of SiO.sub.2, a nitride, or other dielectric material. Its purpose is to seal polycrystalline silicon layer 135 from a subsequent oppositely doped layer. The barrier is intended to be temporary and may be removed in later processing.
In steps 250, second doped amorphous silicon layer 140 is formed overlying
polycrystalline silicon layer 135. Amorphous silicon layer 140 is oppositely
doped from amorphous silicon layer 130. The resulting structure is shown in FIG.
7. In the specific embodiment, amorphous silicon layer 140 is doped with an
n-type material such as phosphene or other n-type dopant. It may be formed with
in-situ doping and CVD deposition. Other embodiments may reverse the order of
the different dopant types in amorphous silicon layers 130 and 140 so that the
p-type layer overlies the n-type layer. Amorphous silicon layer 140 may
alternatively be doped by implantation or diffusion.
In step 260, amorphous silicon layer 140 is annealed using the Excimer laser or other rapid thermal energy process as described in step 240. This results in a transparent polycrystalline silicon layer 145. The resulting structure is shown in FIG. 8. Step 260 also activates the dopant. The barrier formed in step 245 may be removed during the annealing process leaving a P-N junction between layers 135 and 145.
In step 270, a second conductive layer 150 is formed above the P-N junction resulting in solar cell 100 as shown in FIG. 1. In the specific embodiment, the second conductive layer is also ITO that is deposited with CVD at a thickness of about one-half micron over the area of interest. Again, its maximum thickness is dependent upon the desired transparency, conductivity, and flexibility. Second conductive layer 150 may also be optionally annealed to improve the mobility of the electrons and holes.
Steps 220-270 may be performed using a roll-to-roll coater. Such roll-to-roll coaters are well known in the art. Using this technique, large sheets of solar cells 100 may be formed on large rolls of a substrate such as plastic. Processing steps 220-270 are performed with equipment located between the two rolls of the roll-to-roll coater. The Excimer laser is one of these pieces of equipment. It typically outputs a beam that is 0.6 mm wide and extends across the substrate. Multiple lasers may be also be used together to increase the rate of processing over large surface areas. The rolls of plastic may be moved so the entire substrate is exposed to the laser. Alternatively, the laser may be moved over the substrate instead of moving the substrate.
FIG. 9A shows a cross section of solar cell 100 during an embodiment of annealing process of step 240. A sheet of substrate 110 has already been layered with transparent conductor 120 and amorphous silicon 130. A laser 300 resides above the sheet and transmits thermal energy into amorphous silicon 130 converting it to polycrystalline silicon 135 as the sheet moves past laser 300. As described above, laser 300 may be an Excimer laser or other type of laser. The thermal energy output of laser 300 is such that amorphous silicon layer 130 is heated above approximately 1400.degree. C. to convert it to polycrystalline silicon, but substrate 110 remains below 450.degree. C. FIG. 9B shows a thermal graph of the temperature of the sheet through its depth. At the top of amorphous silicon 130, the temperature may be 1450.degree. C. while at the bottom it is approximately 1400.degree. C. Through transparent conductor 120 the temperature declines rapidly until it is less than 450.degree. C. at substrate 110. In the specific embodiment, the laser moves across the sheet slow enough that each pulse of the laser overlaps the portion that was previously exposed to the beam. Preferably the overlap is two thirds the width of the beam. A typical scan rate is 60 mm per second.
In operation, electrodes are provided to each of the p+ and n- polycrystalline silicon layers 135 and 145 to form an electrical circuit. In the presence of optical radiation, the P-N junction of the specific embodiment develops a typical 0.46 volt potential at approximately 7 mA/cm in sunlight. However, it can be constructed such that a wide range of power output is provided. Such outputs can vary by orders of magnitude. The size of the area, the quantum efficiency of the cell (electron-hole mobility/absorptivity) and the energy level of the instant optical energy determines the amount of optical energy converted to electrical current. A typical design efficiency is about 2-3% or better, as compared with an opaque crystalline solar cell with an efficiency of 13%. An advantage of solar cell 100 is that it does not depend on hydrogen as a carrier, so it does not suffer from the efficiency loss that amorphous silicon does. Thus, its lifetime is extended over that of amorphous solar cells.
In another embodiment of the present invention, multiple layers of P-N junctions may be formed by repeating steps 220-270. The resulting multiple layer solar cell may increase the efficiency to more closely resemble that of crystalline solar cells. FIG. 9 is a cross-sectional diagram of a resulting multiple layer solar cell 900. Although solar cell 900 shows only two levels of solar cells, any number may be formed. Since these layers are transparent, the resulting solar cells in the lower levels are exposed to the light even though they are underneath other solar cells. This may be desirable for some applications to increase the efficiency and extend the life of the resulting structure.
Referring to FIG. 10, a single layer solar cell such as solar cell 100 is formed and an additional solar cell is formed above it to form a multiple layer solar cell 900. In some embodiments, second transparent conductor 150 is thicker than first transparent conductor 120. In other embodiments it is the same thickness. In still other embodiments, a dielectric layer (not shown) is formed on another conductive layer (not shown) is formed above the dielectric layer.
A second p+ polycrystalline layer 910 is formed by forming a p+ amorphous silicon layer and annealing it as described above. A second n- polycrystalline layer 910 is formed above second p+ polycrystalline layer 910 by forming an n- amorphous silicon layer and annealing it. A third transparent conductor 930 is formed above that. This process may be repeated to form as many layers as is desirable.
As described briefly above, the reflectivity of solar cell 100 may be varied depending on the application. In some embodiments, it is desirable that the outer conductive layer (i.e., second conductive layer 150) be as anti-reflective as possible, while the inner conductive layer (i.e., first conductive layer 120) is reflective. Such a design will allow the maximum amount of sunlight to be absorbed since it passes through solar cell 100 as it enters and as it is reflected back. Other embodiments may make use of various reflective qualities for functional or aesthetic reasons.
To provide the reflectivity, an embodiment substitutes a flash of silver, aluminum, titanium or other reflective conductor instead of a transparent conductor such as ITO. This substitution can be made on any or all of the conductive layers, depending on the desired reflectivity.
In other embodiments of the present invention, solar cell 100 may also be used as an optical filter. Using the above-described methodology, solar cell 100 provides a photopic response that is very similar to that of the human eye. That is, it absorbs about 20-80% of those light frequencies which are visible to the human eye, while allowing the rest of the visible light to pass through. It can be used as an optical filter alone, or in combination with its use as a solar cell.
While a specific embodiment has been described herein, it will be recognized that the present invention is not limited to the specific embodiment described. For example, the p+ and n- layers 135 and 145 may be reversed. Also, different or new fabrication techniques may be used or other changes made that do not depart from this spirit and scope of the present invention. The invention is intended to be limited only by the attached claims.
ASSIGNMENT OF PATENT
WHEREAS, the undersigned (the "Patentee") did obtain a United States Patent for Transparent Solar Cell and Method of Fabrication (Device), No. 6,180,871, dated January 30, 2001 (the "Patent");
WHEREAS, the Patentee is the sole owner of the Patent;
WHEREAS, XsunX, Inc., a Colorado corporation previously named Sun River Mining, Inc. (the "Assignee") whose mailing address is 7609 Ralston Road, Arvada, CO 80002, desires to acquire the entire right, title, and interest in and to the Patent.
NOW THEREFORE, in consideration for the sum of one dollar ($1.00), shares of the common stock of the Assignee and other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the Patentee does hereby sell, assign, and transfer to the Assignee the entire right, title, and interest in and to the Patent to be held and enjoyed by the Assignee for its own use and on its own behalf, and for its legal representatives and assigns, to the full end of the term for which the Patent has been granted, as fully and entirely as the Patent would have been held by the Patentee had this assignment and sale not been made.
Executed this 25 day of September 2003 at Camarillo, California.
XOPTIX, INC.
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Before me personally appeared said
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and acknowledge that the foregoing instrument to be his free act and deed this 25th day of September, 2003
(Notary Public)
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