Patents by Inventor Walajabad S. Sampath
Walajabad S. Sampath has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Publication number: 20220336687Abstract: The present disclosure relates to thin-film solar cells with improved efficiency and methods for producing thin-film solar cells having increased efficiency. In certain embodiments, thin-film solar cells having an efficiency of over 21%, over 20%, over 19%, over 15%, over 10%, etc. has been obtained using the methods of the disclosure. In certain aspects, the methods of the disclosure use passivation, passivating oxides, and/or doping treatments in increase the efficiency of the thin-film solar cells; e.g., CdTe-based thin-film solar cells.Type: ApplicationFiled: June 10, 2022Publication date: October 20, 2022Applicant: Colorado State University Research FoundationInventors: Walajabad S. Sampath, Amit H. Munshi, Ramesh Pandey, Akash Shah, Tushar Shimpi
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Publication number: 20190341506Abstract: The present disclosure relates to thin-film solar cells with improved efficiency and methods for producing thin-film solar cells having increased efficiency. In certain embodiments, thin-film solar cells having an efficiency of over 21%, over 20%, over 19%, over 15%, over 10%, etc. has been obtained using the methods of the disclosure. In certain aspects, the methods of the disclosure use passivation, passivating oxides, and/or doping treatments in increase the efficiency of the thin-film solar cells; e.g., CdTe-based thin-film solar cells.Type: ApplicationFiled: May 6, 2019Publication date: November 7, 2019Applicant: Colorado State University Research FoundationInventors: Walajabad S. Sampath, Amit H. Munshi, Adam H. Danielson, Kurt L. Barth
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Patent number: 8956698Abstract: Systems and methods for depositing complex thin-film alloys on substrates are provided. In particular, systems and methods for the deposition of thin-film Cd1-xMxTe ternary alloys on substrates using a stacked-source sublimation system are provided, where M is a metal such as Mg, Zn, Mn, and Cu.Type: GrantFiled: April 7, 2014Date of Patent: February 17, 2015Assignee: Colorado State University Research FoundationInventors: Walajabad S. Sampath, Pavel S. Kobyakov, Kevin E. Walters, Davis R. Hemenway
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Publication number: 20140205768Abstract: Systems and methods for depositing complex thin-film alloys on substrates are provided. In particular, systems and methods for the deposition of thin-film Cd1-xMxTe ternary alloys on substrates using a stacked-source sublimation system are provided, where M is a metal such as Mg, Zn, Mn, and Cu.Type: ApplicationFiled: April 7, 2014Publication date: July 24, 2014Applicant: Colorado State University Research FoundationInventors: Walajabad S. Sampath, Pavel S. Kobyakov, Kevin E. Walters, Davis R. Hemenway
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Patent number: 8778081Abstract: Systems and methods for depositing complex thin-film alloys on substrates are provided. In particular, systems and methods for the deposition of thin-film Cd1-xMxTe ternary alloys on substrates using a stacked-source sublimation system are provided, where M is a metal such as Mg, Zn, Mn, and Cu.Type: GrantFiled: January 3, 2013Date of Patent: July 15, 2014Assignee: Colorado State University Research FoundationInventors: Walajabad S. Sampath, Pavel S. Kobyakov, Kevin E. Walters, Davis R. Hemenway
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Apparatus and method for fabricating photovoltaic modules using heated pocket deposition in a vacuum
Patent number: 8557045Abstract: An apparatus and method for manufacturing thin-film CdS/CdTe photovoltaic modules in a vacuum environment. The apparatus deposits CdS and CdTe layers onto a substrate using heated pocket deposition, a form of physical vapor deposition (PVD) in which a material thermally sublimes from a thermal sublimation source block and is deposited onto a substrate. The thermal sublimation source block includes a pocket having a lower surface into which an array of holes is formed to house plugs of deposition material. Upon heating, deposition material sublimes from a surface of each plug of deposition material, and the surface of each plug regresses into its corresponding hole while maintaining a constant surface area. The sublimation surface area of deposition material across the pocket remains substantially constant during an extended deposition process, and the deposition material is substantially free of undesired thermal radiation from the substrate.Type: GrantFiled: August 26, 2008Date of Patent: October 15, 2013Assignee: Colorado State University Research FoundationInventors: Kurt L. Barth, Robert A. Enzenroth, Walajabad S. Sampath -
Patent number: 8302554Abstract: The present invention is directed to an apparatus and method for rapid cooling of a large substrate in a vacuum environment. A first cooled plate is brought into close proximity with one surface of a flat substrate. The spatial volume between the first cooling plate and the substrate is sealed and brought to a higher pressure than the surrounding vacuum level to increase the cooling efficiency. A second cooled plate is brought into close proximity with the opposite surface of the flat substrate. A second spatial volume between the second cooling plate and the substrate is sealed and the gas pressure is equalized to the gas pressure in the first spatial volume. The equalization of the gas pressure on both sides of the flat substrate eliminates deflection of the substrate and bending stress in the substrate.Type: GrantFiled: August 23, 2010Date of Patent: November 6, 2012Assignee: Colorada State University Research Foundation.Inventors: Kurt L. Barth, Robert A. Enzenroth, Walajabad S. Sampath
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Publication number: 20120006809Abstract: Systems, apparatus and methods for in-line evaporative deposition are described herein that include a nickel chromium wire based heating system that can reach desired operating temperatures while providing opportunities for improved temperature uniformity and energy usage. In some embodiments, an apparatus includes a base member configured to be used as a sublimation crucible and the base member defines a channel in a surface of the base member. A first layer of electrically insulating material is disposed within the channel and has a substantially uniform thickness. A heater coil is disposed within the channel such that the first layer of electrically insulating material is disposed between the heater coil and the surface of the base. A second layer of electrically insulating material is disposed on the heater coil such that the heater coil is disposed between the first layer of electrically insulating material and the second layer of electrically insulating material.Type: ApplicationFiled: June 23, 2011Publication date: January 12, 2012Applicant: COLORADO STATE UNIVERSITY RESEARCH FOUNDATIONInventors: Pavel Sergey Kobyakov, Walajabad S. Sampath, Kevin Eugene Walters
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Publication number: 20100314076Abstract: The present invention is directed to an apparatus and method for rapid cooling of a large substrate in a vacuum environment. A first cooled plate is brought into close proximity with one surface of a flat substrate. The spatial volume between the first cooling plate and the substrate is sealed and brought to a higher pressure than the surrounding vacuum level to increase the cooling efficiency. A second cooled plate is brought into close proximity with the opposite surface of the flat substrate. A second spatial volume between the second cooling plate and the substrate is sealed and the gas pressure is equalized to the gas pressure in the first spatial volume. The equalization of the gas pressure on both sides of the flat substrate eliminates deflection of the substrate and bending stress in the substrate.Type: ApplicationFiled: August 23, 2010Publication date: December 16, 2010Inventors: Kurt L. Barth, Robert A. Enzenroth, Walajabad S. Sampath
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Patent number: 7803419Abstract: The present invention is directed to an apparatus and method for rapid cooling of a large substrate in a vacuum environment. A first cooled plate is brought into close proximity with one surface of a flat substrate. The spatial volume between the first cooling plate and the substrate is sealed and brought to a higher pressure than the surrounding vacuum level to increase the cooling efficiency. A second cooled plate is brought into close proximity with the opposite surface of the flat substrate. A second spatial volume between the second cooling plate and the substrate is sealed and the gas pressure is equalized to the gas pressure in the first spatial volume. The equalization of the gas pressure on both sides of the flat substrate eliminates deflection of the substrate and bending stress in the substrate.Type: GrantFiled: September 22, 2006Date of Patent: September 28, 2010Assignee: Abound Solar, Inc.Inventors: Kurt L. Barth, Robert A. Enzenroth, Walajabad S. Sampath
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Apparatus and Method For Fabricating Photovoltaic Modules Using Heated Pocket Deposition In a Vacuum
Publication number: 20100055827Abstract: An apparatus and method for manufacturing thin-film CdS/CdTe photovoltaic modules in a vacuum environment. The apparatus deposits CdS and CdTe layers onto a substrate using heated pocket deposition, a form of physical vapor deposition (PVD) in which a material thermally sublimes from a thermal sublimation source block and is deposited onto a substrate. The thermal sublimation source block includes a pocket having a lower surface into which an array of holes is formed to house plugs of deposition material. Upon heating, deposition material sublimes from a surface of each plug of deposition material, and the surface of each plug regresses into its corresponding hole while maintaining a constant surface area. The sublimation surface area of deposition material across the pocket remains substantially constant during an extended deposition process, and the deposition material is substantially free of undesired thermal radiation from the substrate.Type: ApplicationFiled: August 26, 2008Publication date: March 4, 2010Applicant: AVA SOLAR INC.Inventors: Kurt L. BARTH, Robert A. ENZENROTH, Walajabad S. SAMPATH -
Publication number: 20080075853Abstract: The present invention is directed to an apparatus and method for rapid cooling of a large substrate in a vacuum environment. A first cooled plate is brought into close proximity with one surface of a flat substrate. The spatial volume between the first cooling plate and the substrate is sealed and brought to a higher pressure than the surrounding vacuum level to increase the cooling efficiency. A second cooled plate is brought into close proximity with the opposite surface of the flat substrate. A second spatial volume between the second cooling plate and the substrate is sealed and the gas pressure is equalized to the gas pressure in the first spatial volume. The equalization of the gas pressure on both sides of the flat substrate eliminates deflection of the substrate and bending stress in the substrate.Type: ApplicationFiled: September 22, 2006Publication date: March 27, 2008Inventors: Kurt L. Barth, Robert A. Enzenroth, Walajabad S. Sampath
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Patent number: 7220321Abstract: An apparatus and processes for large scale inline manufacturing of CdTe photovoltaic modules in which all steps, including rapid substrate heating, deposition of CdS, deposition of CdTe, CdCl2 treatment, and ohmic contact formation, are performed within a single vacuum boundary at modest vacuum pressures. A p+ ohmic contact region is formed by subliming a metal salt onto the CdTe layer. A back electrode is formed by way of a low cost spray process, and module scribing is performed by means of abrasive blasting or mechanical brushing through a mask. The vacuum process apparatus facilitates selective heating of substrates and films, exposure of substrates and films to vapor with minimal vapor leakage, deposition of thin films onto a substrate, and stripping thin films from a substrate. A substrate transport apparatus permits the movement of substrates into and out of vacuum during the thin film deposition processes, while preventing the collection of coatings on the substrate transport apparatus itself.Type: GrantFiled: March 24, 2004Date of Patent: May 22, 2007Inventors: Kurt L. Barth, Robert A. Enzenroth, Walajabad S. Sampath
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Publication number: 20030129810Abstract: An apparatus and processes for large scale inline manufacturing of CdTe photovoltaic modules in which all steps, including rapid substrate heating, deposition of CdS, deposition of CdTe, CdCl2 treatment, and ohmic contact formation, are performed within a single vacuum boundary at modest vacuum pressures. A p+ ohmic contact region is formed by subliming a metal salt onto the CdTe layer. A back electrode is formed by way of a low cost spray process, and module scribing is performed by means of abrasive blasting or mechanical brushing through a mask. The vacuum process apparatus facilitates selective heating of substrates and films, exposure of substrates and films to vapor with minimal vapor leakage, deposition of thin films onto a substrate, and stripping thin films from a substrate. A substrate transport apparatus permits the movement of substrates into and out of vacuum during the thin film deposition processes, while preventing the collection of coatings on the substrate transport apparatus itself.Type: ApplicationFiled: July 22, 2002Publication date: July 10, 2003Inventors: Kurt L. Barth, Robert A. Enzenroth, Walajabad S. Sampath
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Patent number: 6423565Abstract: An apparatus and processes for large scale inline manufacturing of CdTe photovoltaic modules in which all steps, including rapid substrate heating, deposition of CdS, deposition of CdTe, CdCl2 treatment, and ohmic contact formation, are performed within a single vacuum boundary at modest vacuum pressures. A p+ ohmic contact region is formed by subliming a metal salt onto the CdTe layer. A back electrode is formed by way of a low cost spray process, and module scribing is performed by means of abrasive blasting or mechanical brushing through a mask. The vacuum process apparatus facilitates selective heating of substrates and films, exposure of substrates and films to vapor with minimal vapor leakage, deposition of thin films onto a substrate, and stripping thin films from a substrate. A substrate transport apparatus permits the movement of substrates into and out of vacuum during the thin film deposition processes, while preventing the collection of coatings on the substrate transport apparatus itself.Type: GrantFiled: May 30, 2000Date of Patent: July 23, 2002Inventors: Kurt L. Barth, Robert A. Enzenroth, Walajabad S. Sampath
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Patent number: 5032421Abstract: This invention includes a method featuring steps having a transport (64, 68) to carry metal articles (10, 14) through a vacuum chamber (62, 66, 90) containing a plasma cleaning station (32) followed by exposure to an evaporant of metal (42) generated by an E-Beam (50) caused to condense on the articles in high vacuum. A channel structure (51) is provided to cause selective condensation upon the surface of said articles. The apparatus includes several stations (101, 102, 103) to provide multiple coatings on one or both sides of an article to be coated.Type: GrantFiled: August 21, 1990Date of Patent: July 16, 1991Assignee: AMP IncorporatedInventors: Srinivasan V. Sarma, Walajabad S. Sampath, Nagarajan Subramanian, Paul J. Wilbur
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Patent number: 4900579Abstract: A process for applying and bonding a solid lubricant on a substrate whose surface has depressions and pores. The process comprises depositing fine solid lubricant particles on the surface of a substrate to be lubricated in excess of a quantity sufficient to fill essentially all depressions and pores on the substrate surface, and thereafter burnishing the substrate to distribute and bond the lubricant particles on the substrate. Such burnishing of the substrate can be accomplished during its moving contact with another substrate during intended use. Maintenance of lubricity can be accomplished by depositing additional lubricant particles on the substrate and thereafter burnishing, and can be performed while the substrate is in moving contact with another substrate whereby this moving contact performs the burnishing operation.Type: GrantFiled: February 18, 1988Date of Patent: February 13, 1990Assignee: Adolph Coors CompanyInventors: Kyu Y. Lee, Walajabad S. Sampath, Samuel C. Wu