Patents by Inventor Subhendu Guha

Subhendu Guha 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: 20130000717
    Abstract: A photovoltaic device and processes of manufacture are provided that employ particularly configured, textured back reflector structures that maintain a smooth, non-textured surface at the interface between the lowermost doped layer of semiconductor material and the intrinsic, light absorbing layer of nanocrystalline semiconductor material. The back reflector structure provides exhibit both superior short circuit current and a superior fill factor to a photovoltaic device such as those using nanocrystalline semiconductor materials.
    Type: Application
    Filed: June 29, 2012
    Publication date: January 3, 2013
    Applicant: United Solar Ovonic LLC
    Inventors: Subhendu Guha, Chi Yang, Baojie Yan
  • Publication number: 20110220177
    Abstract: A tandem photovoltaic device includes at least two photovoltaic cells stacked in an optical and electrical series relationship. At least one of the tandem cells includes a dual function semiconductor layer fabricated from a dual function semiconductor material. This dual function layer is an electronically active constituent of the cell. The dual function layer also is optically active and creates a reflective condition which redirects a portion of the light which has passed through the cell back through the cell's active layers to photo generate additional photocurrent. Use of the dual function material eliminates the need for incorporating separate semiconductor and reflective layers in a photovoltaic device. Further disclosed are exemplary formulations of some dual function materials.
    Type: Application
    Filed: March 10, 2010
    Publication date: September 15, 2011
    Applicant: United Solar Ovonic LLC
    Inventors: Baojie Yan, Subhendu Guha, Chi Yang
  • Patent number: 7964476
    Abstract: A system for the laser scribing of semiconductor devices includes a laser light source operable to selectably deliver laser illumination at a first wavelength and at a second wavelength which is shorter than the first wavelength. The system further includes a support for a semiconductor device and an optical system which is operative to direct the laser illumination from the light source to the semiconductor device. The optical system includes optical elements which are compatible with the laser illumination of the first wavelength and the laser illumination of the second wavelength. In specific instances, the first wavelength is long wavelength illumination such as illumination of at least 1000 nanometers, and the second wavelength is short wavelength illumination which in specific instances is 300 nanometers or shorter. By the use of the differing wavelengths, specific layers of the semiconductor device may be scribed without damage to subjacent layers. Also disclosed are specific scribing processes.
    Type: Grant
    Filed: March 24, 2008
    Date of Patent: June 21, 2011
    Assignee: United Solar Ovonic LLC
    Inventors: Shengzhong Liu, Ginger Pietka, Kevin Beernink, Arindam Banerjee, Chi Yang, Subhendu Guha
  • Patent number: 7902049
    Abstract: A process for the plasma deposition of a layer of a microcrystalline semiconductor material is carried out by energizing a process gas which includes a precursor of the semiconductor material and a diluent with electromagnetic energy so as to create a plasma therefrom. The plasma deposits a layer of the microcrystalline semiconductor material onto the substrate. The concentration of the diluent in the process gas is varied as a function of the thickness of the layer of microcrystalline semiconductor material which has been deposited. Also disclosed is the use of the process for the preparation of an N-I-P type photovoltaic device.
    Type: Grant
    Filed: January 27, 2004
    Date of Patent: March 8, 2011
    Assignee: United Solar Ovonic LLC
    Inventors: Subhendu Guha, Chi C. Yang, Baojie Yan
  • Publication number: 20100205877
    Abstract: A mounting system for securing a photovoltaic device to a surface is provided in accordance with an exemplary embodiment. The mounting system includes one or more mounting members for securing an inactive area of the photovoltaic device to the surface. The mounting members are configured so the inactive area is non-destructively detachable from the surface and the photovoltaic device is not made incapable of operation due the detachment process. In an exemplary embodiment, the mounting system includes a unique configuration of mounting members for securing the photovoltaic device against the surface during a predetermined load condition imposed upon the photovoltaic device.
    Type: Application
    Filed: February 13, 2009
    Publication date: August 19, 2010
    Inventors: Uday Varde, Jonathan Call, Subhendu Guha
  • Publication number: 20100200067
    Abstract: A metal and oxygen material such as a transparent electrically conductive oxide material is electro deposited onto a substrate in a solution deposition process. Process parameters are controlled so as to result in the deposition of a high quality layer of material which is suitable for use in a back reflector structure of a high efficiency photovoltaic device. The deposition may be carried out in conjunction with a masking member which operates to restrict the deposition of the metal and oxygen material to specific portions of the substrate. In particular instances the deposition may be implemented in a continuous, roll-to-roll process. Further disclosed are semiconductor devices and components of semiconductor devices made by the present process, as well as apparatus for carrying out the process.
    Type: Application
    Filed: February 11, 2009
    Publication date: August 12, 2010
    Applicant: United Solar Ovonic LLC
    Inventors: Shengzhong Liu, Yanhua Zhou, Chaolan Hu, Arindam Banerjee, Jeffrey Yang, Subhendu Guha
  • Publication number: 20100200411
    Abstract: A metal and oxygen material such as a transparent electrically conductive oxide material is electro deposited onto a substrate in a solution deposition process. Process parameters are controlled so as to result in the deposition of a high quality layer of material which is suitable for use in a back reflector structure of a high efficiency photovoltaic device The deposition may be carried out in conjunction with a masking member which operates to restrict the deposition of the metal and oxygen material to specific portions of the substrate. In particular instances the deposition may be implemented in a continuous, roll-to-roll process. Further disclosed are semiconductor devices and components of semiconductor devices made by the present process, as well as apparatus for carrying out the process.
    Type: Application
    Filed: February 11, 2009
    Publication date: August 12, 2010
    Applicant: United Solar Ovonic LLC
    Inventors: Shengzhong Liu, Chaolan Hu, Yanhua Zhou, Arindam Banerjee, Jeffrey Yang, Subhendu Guha
  • Publication number: 20100200413
    Abstract: A metal and oxygen material such as a transparent electrically conductive oxide material is electro deposited onto a substrate in a solution deposition process. Process parameters are controlled so as to result in the deposition of a high quality layer of material which is suitable for use in a back reflector structure of a high efficiency photovoltaic device. The deposition may be carried out in conjunction with a masking member which operates to restrict the deposition of the metal and oxygen material to specific portions of the substrate. In particular instances the deposition may be implemented in a continuous, roll-to-roll process. Further disclosed are semiconductor devices and components of semiconductor devices made by the present process, as well as apparatus for carrying out the process.
    Type: Application
    Filed: February 11, 2009
    Publication date: August 12, 2010
    Applicant: United Solar Ovonic LLC
    Inventors: Shengzhong Liu, Chaolan Hu, Yanhua Zhou, Arindam Banerjee, Jeffrey Yang, Subhendu Guha
  • Publication number: 20100200408
    Abstract: A metal and oxygen material such as a transparent electrically conductive oxide material is electro deposited onto a substrate in a solution deposition process. Process parameters are controlled so as to result in the deposition of a high quality layer of material which is suitable for use in a back reflector structure of a high efficiency photovoltaic device. The deposition may be carried out in conjunction with a masking member which operates to restrict the deposition of the metal and oxygen material to specific portions of the substrate. In particular instances the deposition may be implemented in a continuous, roll-to-roll process. Further disclosed are semiconductor devices and components of semiconductor devices made by the present process, as well as apparatus for carrying out the process.
    Type: Application
    Filed: February 11, 2009
    Publication date: August 12, 2010
    Applicant: United Solar Ovonic LLC
    Inventors: Shengzhong Liu, Chaolan Hu, Yanhua Zhou, Kais Younan, Bud Dotter, II, Vincent Cannella, Arindam Banerjee, Jeffrey Yang, Subhendu Guha
  • Publication number: 20100200409
    Abstract: A metal and oxygen material such as a transparent electrically conductive oxide material is electro deposited onto a substrate in a solution deposition process. Process parameters are controlled so as to result in the deposition of a high quality layer of material which is suitable for use in a back reflector structure of a high efficiency photovoltaic device. The deposition may be carried out in conjunction with a masking member which operates to restrict the deposition of the metal and oxygen material to specific portions of the substrate. In particular instances the deposition may be implemented in a continuous, roll-to-roll process. Further disclosed are semiconductor devices and components of semiconductor devices made by the present process, as well as apparatus for carrying out the process.
    Type: Application
    Filed: February 11, 2009
    Publication date: August 12, 2010
    Applicant: United Solar Ovonic LLC
    Inventors: Shengzhong Liu, Chaolan Hu, Yanhua Zhou, Kais Younan, Bud Dotter, II, Vincent Cannella, Arindam Banerjee, Jeffrey Yang, Subhendu Guha
  • Publication number: 20100116334
    Abstract: A VHF energized plasma deposition process wherein a process gas is decomposed in a plasma so as to deposit the thin film material onto a substrate, is carried out at process gas pressures which are in the range of 0.5-2.0 torr, with substrate temperatures that do not exceed 300° C., and substrate-cathode spacings in the range of 10-50 millimeters. Deposition rates are at least 5 angstroms per second. The present method provides for the high speed deposition of semiconductor materials having a quality at least equivalent to materials produced at a much lower deposition rate.
    Type: Application
    Filed: November 7, 2008
    Publication date: May 13, 2010
    Applicant: United Solar Ovonic LLC
    Inventors: Xixiang Xu, David Alan Beglau, Guozhen Yue, Baojie Yan, Yang Li, Scott Jones, Subhendu Guha, Chi Yang
  • Publication number: 20100117172
    Abstract: A thin film, hydrogenated, silicon based semiconductor alloy material is produced by a VHF energized plasma deposition process wherein a process gas is decomposed in a plasma so as to deposit the thin film material onto a substrate. The process is carried out at process gas pressures which are in the range of 0.5-2.0 torr, with substrate temperatures that do not exceed 300° C., and substrate-cathode spacings in the range of 10-50 millimeters. Deposition rates are at least 5 angstroms per second. Also disclosed are photovoltaic devices which include the semiconductor material.
    Type: Application
    Filed: November 7, 2008
    Publication date: May 13, 2010
    Applicant: United Solar Ovonic LLC
    Inventors: Baojie Yan, Xixiang Xu, Guozhen Yue, Subhendu Guha, Chi Yang
  • Publication number: 20100116338
    Abstract: A hydrogenated, silicon based semiconductor alloy has a defect density of less than 1016 cm?3. The alloy may comprise a hydrogenated silicon alloy or a hydrogenated silicon-germanium alloy. Hydrogen content of the alloy is generally less than 15%, and in some instances less than 11%. The tandem photovoltaic devices which incorporate the alloy exhibit low levels of photo degradation. In some instances, the material is fabricated by a high speed VHF deposition process.
    Type: Application
    Filed: November 7, 2008
    Publication date: May 13, 2010
    Applicant: United Solar Ovinic LLC
    Inventors: Xixiang Xu, Subhendu Guha, Chi Yang
  • Patent number: 7517465
    Abstract: An ultra lightweight semiconductor device such as a photovoltaic device is fabricated on a non-etchable barrier layer which is disposed upon an etchable substrate. The device is contacted with an appropriate etchant for a period of time sufficient to remove at least a portion of the thickness of the substrate. The barrier layer prevents damage to the photovoltaic material during the etching process. Photovoltaic devices fabricated by this method have specific power levels in excess of 300 w/kg.
    Type: Grant
    Filed: October 20, 2005
    Date of Patent: April 14, 2009
    Assignee: United Solar Ovonic LLC
    Inventors: Subhendu Guha, Arindam Banerjee, Kevin Beernink, Todd Johnson, Ginger Pietka, Gregory DeMaggio, Shengzhong (Frank) Liu, Jeffrey Yang
  • Publication number: 20090075483
    Abstract: An ultra lightweight semiconductor device such as a photovoltaic device is fabricated on a non-etchable barrier layer which is disposed upon an etchable substrate. The device is contacted with an appropriate etchant for a period of time sufficient to remove at least a portion of the thickness of the substrate. The barrier layer prevents damage to the photovoltaic material during the etching process. Photovoltaic devices fabricated by this method have specific power levels in excess of 300 w/kg.
    Type: Application
    Filed: October 20, 2005
    Publication date: March 19, 2009
    Inventors: Subhendu Guha, Arindam Banerjee, Kevin Beernink, Todd Johnson, Ginger Pietka, Gregory DeMaggio, Shengzhong (Frank) Liu, Jeffrey Yang
  • Publication number: 20090029053
    Abstract: Darkening of silicone containing materials caused by exposure to ultraviolet illumination is prevented or reversed by exposure of those materials to an atmosphere containing a reactive species, which may comprise activated oxygen. The activated oxygen may be generated by ultraviolet irradiation of the silicone material in an oxygen containing atmosphere. In other instances, the activated oxygen may comprise ozone or some other activated oxygen species. In yet other instances, the reactive species may comprise an oxygen containing material such as nitrous oxide or nitrates. It may also comprise other materials such as halogens, atomic hydrogen, protons or the like. The treatment may be applied prior to ultraviolet exposure so as to prevent or minimize darkening, or it may be applied after darkening has occurred for purposes of reversing the darkening.
    Type: Application
    Filed: July 25, 2007
    Publication date: January 29, 2009
    Applicant: United Solar Ovonic LLC
    Inventors: Shengzhong Liu, Arindam Banerjee, Chi Yang, Subhendu Guha
  • Publication number: 20080233715
    Abstract: A system for the laser scribing of semiconductor devices includes a laser light source operable to selectably deliver laser illumination at a first wavelength and at a second wavelength which is shorter than the first wavelength. The system further includes a support for a semiconductor device and an optical system which is operative to direct the laser illumination from the light source to the semiconductor device. The optical system includes optical elements which are compatible with the laser illumination of the first wavelength and the laser illumination of the second wavelength. In specific instances, the first wavelength is long wavelength illumination such as illumination of at least 1000 nanometers, and the second wavelength is short wavelength illumination which in specific instances is 300 nanometers or shorter. By the use of the differing wavelengths, specific layers of the semiconductor device may be scribed without damage to subjacent layers. Also disclosed are specific scribing processes.
    Type: Application
    Filed: March 24, 2008
    Publication date: September 25, 2008
    Inventors: Shengzhong Liu, Ginger Pietka, Kevin Beernink, Arindam Banerjee, Chi Yang, Subhendu Guha
  • Publication number: 20080173349
    Abstract: A light weight photovoltaic device for use in stratospheric and outer space applications. The device includes a protective surface coating on the light incident side thereof. The protective coating does not deleteriously affect the photovoltaic properties of the solar cell, is formed of a material which protects said solar cell from the harsh conditions in the stratospheric or outer space environment in which the photovoltaic device is adapted to be used; and remains substantially unchanged when exposed to the harsh conditions in the stratosphere or outer space. The protective coating is preferably made of a spray coated silicone based material and is between 0.01 and 2 mil thick.
    Type: Application
    Filed: January 22, 2007
    Publication date: July 24, 2008
    Inventors: Shengzhoug Liu, Kevin Beernink, Arindam Banerjee, Chi-Chung Yang, Subhendu Guha
  • Publication number: 20070256734
    Abstract: A semiconductor device of p-i-n type configuration includes a p layer which is comprised of a p-doped semiconductor material, an n layer comprised of an n-doped semiconductor material and an i layer comprised of a substantially intrinsic, nanocrystalline semiconductor material interposed therebetween. The crystalline volume in the i layer decreases as the thickness of said layer increases from its interface with the n layer to its interface with the p layer. The grain size of the substantially intrinsic nanocrystalline semiconductor material may also decrease as the thickness of the i layer increases from its interface with the n layer to its interface with the p layer. The volume of regions of intermediate range order in a portion of the i layer commencing at the interface of the i layer and the p layer, and comprising no more than 50% of the thickness thereof, is greater than is the volume of regions of intermediate range order in the remainder of the i layer.
    Type: Application
    Filed: May 7, 2007
    Publication date: November 8, 2007
    Inventors: Subhendu Guha, Chi Yang, Baojie Yan, Guozhen Yue
  • Publication number: 20050166955
    Abstract: A support system for retaining a photovoltaic device on a generally planar surface, without any mechanical connection to the surface, includes a frame assembly which rests upon the surface and supports one or more photovoltaic devices in a spaced apart relationship with the surface. At least one ballast pan is attached to the frame assembly. The ballast pan is configured to retain a ballast material therein. The ballast pan may comprise a peripheral ballast pan which extends along the perimeter of the assembly or it may comprise an internal ballast pan which is disposed beneath the photovoltaic device. Also disclosed herein is a method for using the support system.
    Type: Application
    Filed: December 8, 2004
    Publication date: August 4, 2005
    Inventors: Prem Nath, Subhendu Guha