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).

  • Publication number: 20220336687
    Abstract: 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: Application
    Filed: June 10, 2022
    Publication date: October 20, 2022
    Applicant: Colorado State University Research Foundation
    Inventors: Walajabad S. Sampath, Amit H. Munshi, Ramesh Pandey, Akash Shah, Tushar Shimpi
  • Publication number: 20190341506
    Abstract: 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: Application
    Filed: May 6, 2019
    Publication date: November 7, 2019
    Applicant: Colorado State University Research Foundation
    Inventors: Walajabad S. Sampath, Amit H. Munshi, Adam H. Danielson, Kurt L. Barth
  • Patent number: 8956698
    Abstract: 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: Grant
    Filed: April 7, 2014
    Date of Patent: February 17, 2015
    Assignee: Colorado State University Research Foundation
    Inventors: Walajabad S. Sampath, Pavel S. Kobyakov, Kevin E. Walters, Davis R. Hemenway
  • Publication number: 20140205768
    Abstract: 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: Application
    Filed: April 7, 2014
    Publication date: July 24, 2014
    Applicant: Colorado State University Research Foundation
    Inventors: Walajabad S. Sampath, Pavel S. Kobyakov, Kevin E. Walters, Davis R. Hemenway
  • Patent number: 8778081
    Abstract: 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: Grant
    Filed: January 3, 2013
    Date of Patent: July 15, 2014
    Assignee: Colorado State University Research Foundation
    Inventors: Walajabad S. Sampath, Pavel S. Kobyakov, Kevin E. Walters, Davis R. Hemenway
  • Patent number: 8557045
    Abstract: 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: Grant
    Filed: August 26, 2008
    Date of Patent: October 15, 2013
    Assignee: Colorado State University Research Foundation
    Inventors: Kurt L. Barth, Robert A. Enzenroth, Walajabad S. Sampath
  • Patent number: 8302554
    Abstract: 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: Grant
    Filed: August 23, 2010
    Date of Patent: November 6, 2012
    Assignee: Colorada State University Research Foundation.
    Inventors: Kurt L. Barth, Robert A. Enzenroth, Walajabad S. Sampath
  • Publication number: 20120006809
    Abstract: 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: Application
    Filed: June 23, 2011
    Publication date: January 12, 2012
    Applicant: COLORADO STATE UNIVERSITY RESEARCH FOUNDATION
    Inventors: Pavel Sergey Kobyakov, Walajabad S. Sampath, Kevin Eugene Walters
  • Publication number: 20100314076
    Abstract: 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: Application
    Filed: August 23, 2010
    Publication date: December 16, 2010
    Inventors: Kurt L. Barth, Robert A. Enzenroth, Walajabad S. Sampath
  • Patent number: 7803419
    Abstract: 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: Grant
    Filed: September 22, 2006
    Date of Patent: September 28, 2010
    Assignee: Abound Solar, Inc.
    Inventors: Kurt L. Barth, Robert A. Enzenroth, Walajabad S. Sampath
  • Publication number: 20100055827
    Abstract: 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: Application
    Filed: August 26, 2008
    Publication date: March 4, 2010
    Applicant: AVA SOLAR INC.
    Inventors: Kurt L. BARTH, Robert A. ENZENROTH, Walajabad S. SAMPATH
  • Publication number: 20080075853
    Abstract: 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: Application
    Filed: September 22, 2006
    Publication date: March 27, 2008
    Inventors: Kurt L. Barth, Robert A. Enzenroth, Walajabad S. Sampath
  • Patent number: 7220321
    Abstract: 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: Grant
    Filed: March 24, 2004
    Date of Patent: May 22, 2007
    Inventors: Kurt L. Barth, Robert A. Enzenroth, Walajabad S. Sampath
  • Publication number: 20030129810
    Abstract: 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: Application
    Filed: July 22, 2002
    Publication date: July 10, 2003
    Inventors: Kurt L. Barth, Robert A. Enzenroth, Walajabad S. Sampath
  • Patent number: 6423565
    Abstract: 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: Grant
    Filed: May 30, 2000
    Date of Patent: July 23, 2002
    Inventors: Kurt L. Barth, Robert A. Enzenroth, Walajabad S. Sampath
  • Patent number: 5032421
    Abstract: 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: Grant
    Filed: August 21, 1990
    Date of Patent: July 16, 1991
    Assignee: AMP Incorporated
    Inventors: Srinivasan V. Sarma, Walajabad S. Sampath, Nagarajan Subramanian, Paul J. Wilbur
  • Patent number: 4900579
    Abstract: 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: Grant
    Filed: February 18, 1988
    Date of Patent: February 13, 1990
    Assignee: Adolph Coors Company
    Inventors: Kyu Y. Lee, Walajabad S. Sampath, Samuel C. Wu