Patents by Inventor Davood Shahrjerdi

Davood Shahrjerdi 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: 20190237511
    Abstract: Hybrid high electron mobility field-effect transistors including inorganic channels and organic gate barrier layers are used in some applications for forming high resolution active matrix displays. Arrays of such high electron mobility field-effect transistors are electrically connected to thin film switching transistors and provide high drive currents for passive devices such as organic light emitting diodes. The organic gate barrier layers are operative to suppress both electron and hole transport between the inorganic channel layer and the gate electrodes of the high electron mobility field-effect transistors.
    Type: Application
    Filed: April 6, 2019
    Publication date: August 1, 2019
    Inventors: Ali Afzali-Ardakani, Bahman Hekmatshoartabari, Devendra K. Sadana, Davood Shahrjerdi
  • Publication number: 20190198696
    Abstract: A photovoltaic device and method include a doped germanium-containing substrate, an emitter contact coupled to the substrate on a first side and a back contact coupled to the substrate on a side opposite the first side. The emitter includes at least one doped layer of an opposite conductivity type as that of the substrate and the back contact includes at least one doped layer of the same conductivity type as that of the substrate. The at least one doped layer of the emitter contact or the at least one doped layer of the back contact is in direct contact with the substrate, and the at least one doped layer of the emitter contact or the back contact includes an n-type material having an electron affinity smaller than that of the substrate, or a p-type material having a hole affinity larger than that of the substrate.
    Type: Application
    Filed: February 26, 2019
    Publication date: June 27, 2019
    Inventors: Stephen W. Bedell, Keith E. Fogel, Bahman Hekmatshoar-Tabari, Devendra K. Sadana, Ghavam G. Shahidi, Davood Shahrjerdi
  • Patent number: 10312400
    Abstract: A multi-junction solar cell comprising a high-crystalline silicon solar cell and a high-crystalline germanium solar cell. The high-crystalline silicon solar including a first p-doped layer and a n+ layer and the high-crystalline germanium solar cell including a second p layer and a heavily doped layer. The multi-junction solar cell can also be comprised of a heavily doped silicon layer on a non-light receiving back surface of the high-crystalline germanium solar cell and a tunnel junction between the high-crystalline silicon solar cell and the high-crystalline germanium solar cell.
    Type: Grant
    Filed: October 18, 2016
    Date of Patent: June 4, 2019
    Assignee: International Business Machines Corporation
    Inventors: Anirban Basu, Bahman Hekmatshoartabari, Davood Shahrjerdi
  • Patent number: 10304985
    Abstract: A photovoltaic device and method include a doped germanium-containing substrate, an emitter contact coupled to the substrate on a first side and a back contact coupled to the substrate on a side opposite the first side. The emitter includes at least one doped layer of an opposite conductivity type as that of the substrate and the back contact includes at least one doped layer of the same conductivity type as that of the substrate. The at least one doped layer of the emitter contact or the at least one doped layer of the back contact is in direct contact with the substrate, and the at least one doped layer of the emitter contact or the back contact includes an n-type material having an electron affinity smaller than that of the substrate, or a p-type material having a hole affinity larger than that of the substrate.
    Type: Grant
    Filed: May 20, 2015
    Date of Patent: May 28, 2019
    Assignee: International Business Machines Corporation
    Inventors: Stephen W. Bedell, Keith E. Fogel, Bahman Hekmatshoar-Tabari, Devendra K. Sadana, Ghavam G. Shahidi, Davood Shahrjerdi
  • Patent number: 10304986
    Abstract: A photovoltaic device and method include a substrate coupled to an emitter side structure on a first side of the substrate and a back side structure on a side opposite the first side of the substrate. The emitter side structure or the back side structure include layers alternating between wide band gap layers and narrow band gap layers to provide a multilayer contact with an effectively increased band offset with the substrate and/or an effectively higher doping level over a single material contact. An emitter contact is coupled to the emitter side structure on a light collecting end portion of the device. A back contact is coupled to the back side structure opposite the light collecting end portion.
    Type: Grant
    Filed: June 14, 2017
    Date of Patent: May 28, 2019
    Assignee: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Bahman Hekmatshoar-Tabari, Devendra K. Sadana, Ghavam G. Shahidi, Davood Shahrjerdi
  • Patent number: 10304984
    Abstract: A photovoltaic device and method include a doped germanium-containing substrate, an emitter contact coupled to the substrate on a first side and a back contact coupled to the substrate on a side opposite the first side. The emitter includes at least one doped layer of an opposite conductivity type as that of the substrate and the back contact includes at least one doped layer of the same conductivity type as that of the substrate. The at least one doped layer of the emitter contact or the at least one doped layer of the back contact is in direct contact with the substrate, and the at least one doped layer of the emitter contact or the back contact includes an n-type material having an electron affinity smaller than that of the substrate, or a p-type material having a hole affinity larger than that of the substrate.
    Type: Grant
    Filed: September 7, 2012
    Date of Patent: May 28, 2019
    Assignee: International Business Machines Corporation
    Inventors: Stephen W. Bedell, Keith E. Fogel, Bahman Hekmatshoar-Tabari, Devendra K. Sadana, Ghavam G. Shahidi, Davood Shahrjerdi
  • Patent number: 10304944
    Abstract: A method of forming a semiconductor structure is provided. The method including forming a first vertical channel on a first layer of source/drain material that is perpendicular relative to the first vertical channel, and forming a first source/drain semiconductor structure by removing one or more portions of the first layer of source/drain material such that i) the first source/drain semiconductor structure has a vertical side that is substantially planar with a vertical side of the first vertical channel and ii) a width of the source/drain is greater than a width of the first vertical channel, wherein the first source/drain semiconductor structure extends perpendicularly from its vertical side farther than the first vertical channel extends perpendicularly from its vertical side.
    Type: Grant
    Filed: July 18, 2016
    Date of Patent: May 28, 2019
    Assignee: International Business Machines Corporation
    Inventors: Kangguo Cheng, Wilfried E. Haensch, Ali Khakifirooz, Davood Shahrjerdi
  • Publication number: 20190157488
    Abstract: Photovoltaic devices such as solar cells having one or more field-effect hole or electron inversion/accumulation layers as contact regions are configured such that the electric field required for charge inversion and/or accumulation is provided by the output voltage of the photovoltaic device or that of an integrated solar cell unit. In some embodiments, a power source may be connected between a gate electrode and a contact region on the opposite side of photovoltaic device. In other embodiments, the photovoltaic device or integrated unit is self-powering.
    Type: Application
    Filed: January 6, 2019
    Publication date: May 23, 2019
    Inventors: Bahman Hekmatshoartabari, Devendra K. Sadana, Wilfried E. Haensch, Ghavam G. Shahidi, Davood Shahrjerdi
  • Patent number: 10283663
    Abstract: A photovoltaic device that includes an upper cell that absorbs a first range of wavelengths of light and a bottom cell that absorbs a second range of wavelengths of light. The bottom cell includes a heterojunction comprising a crystalline germanium containing (Ge) layer. At least one surface of the crystalline germanium (Ge) containing layer is in contact with a silicon (Si) containing layer having a larger band gap than the crystalline (Ge) containing layer.
    Type: Grant
    Filed: June 10, 2016
    Date of Patent: May 7, 2019
    Assignee: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Keith E. Fogel, Bahman Hekmatshoartabari, Devendra K. Sadana, Ghavam G. Shahidi, Davood Shahrjerdi
  • Publication number: 20190123230
    Abstract: A photovoltaic device and method include a substrate coupled to an emitter side structure on a first side of the substrate and a back side structure on a side opposite the first side of the substrate. The emitter side structure or the back side structure include layers alternating between wide band gap layers and narrow band gap layers to provide a multilayer contact with an effectively increased band offset with the substrate and/or an effectively higher doping level over a single material contact. An emitter contact is coupled to the emitter side structure on a light collecting end portion of the device. A back contact is coupled to the back side structure opposite the light collecting end portion.
    Type: Application
    Filed: December 12, 2018
    Publication date: April 25, 2019
    Inventors: Bahman Hekmatshoar-Tabari, Devendra K. Sadana, Ghavam G. Shahidi, Davood Shahrjerdi
  • Patent number: 10256357
    Abstract: A method for fabricating a device with integrated photovoltaic cells includes supporting a semiconductor substrate on a first handle substrate and doping the semiconductor substrate to form doped alternating regions with opposite conductivity. A doped layer is formed over a first side the semiconductor substrate. A conductive material is patterned over the doped layer to form conductive islands such that the conductive islands are aligned with the alternating regions to define a plurality of photovoltaic cells connected in series on a monolithic structure.
    Type: Grant
    Filed: November 14, 2017
    Date of Patent: April 9, 2019
    Assignee: International Business Machines Corporation
    Inventors: Stephen W. Bedell, Bahman Hekmatshoartabari, Devendra K. Sadana, Ghavam G. Shahidi, Davood Shahrjerdi
  • Patent number: 10256363
    Abstract: The present invention relates generally to semiconductor devices and more particularly, to a structure and method of forming a photovoltaic cell using a surface treatment to improve device performance. Embodiments of the present invention may improve open circuit voltage, fill factor, and energy conversion efficiency by performing a surface treatment on an upper surface of an absorber layer. The surface treatment may improve device performance by permitting a more cohesive interface between the upper surface of the absorber layer and a lower surface of a passivation layer. The more cohesive interface may allow carriers to move from one layer to another with less resistance, and thus, increase device performance.
    Type: Grant
    Filed: October 25, 2017
    Date of Patent: April 9, 2019
    Assignee: International Business Machines Corporation
    Inventors: Ning Li, Devendra K. Sadana, Davood Shahrjerdi
  • Patent number: 10256276
    Abstract: Hybrid high electron mobility field-effect transistors including inorganic channels and organic gate barrier layers are used in some applications for forming high resolution active matrix displays. Arrays of such high electron mobility field-effect transistors are electrically connected to thin film switching transistors and provide high drive currents for passive devices such as organic light emitting diodes. The organic gate barrier layers are operative to suppress both electron and hole transport between the inorganic channel layer and the gate electrodes of the high electron mobility field-effect transistors.
    Type: Grant
    Filed: October 24, 2016
    Date of Patent: April 9, 2019
    Assignee: International Business Machines Corporation
    Inventors: Ali Afzali-Ardakani, Bahman Hekmatshoartabari, Devendra K. Sadana, Davood Shahrjerdi
  • Patent number: 10199524
    Abstract: Photovoltaic devices such as solar cells having one or more field-effect hole or electron inversion/accumulation layers as contact regions are configured such that the electric field required for charge inversion and/or accumulation is provided by the output voltage of the photovoltaic device or that of an integrated solar cell unit. In some embodiments, a power source may be connected between a gate electrode and a contact region on the opposite side of photovoltaic device. In other embodiments, the photovoltaic device or integrated unit is self-powering.
    Type: Grant
    Filed: January 13, 2012
    Date of Patent: February 5, 2019
    Assignee: International Business Machines Corporation
    Inventors: Bahman Hekmatshoartabari, Devendra K. Sadana, Wilfried E. Haensch, Ghavam G. Shahidi, Davood Shahrjerdi
  • Patent number: 10177266
    Abstract: A photovoltaic device and method include a substrate coupled to an emitter side structure on a first side of the substrate and a back side structure on a side opposite the first side of the substrate. The emitter side structure or the back side structure include layers alternating between wide band gap layers and narrow band gap layers to provide a multilayer contact with an effectively increased band offset with the substrate and/or an effectively higher doping level over a single material contact. An emitter contact is coupled to the emitter side structure on a light collecting end portion of the device. A back contact is coupled to the back side structure opposite the light collecting end portion.
    Type: Grant
    Filed: December 22, 2015
    Date of Patent: January 8, 2019
    Assignee: International Business Machines Corporation
    Inventors: Bahman Hekmatshoar-Tabari, Devendra K. Sadana, Ghavam G. Shahidi, Davood Shahrjerdi
  • Patent number: 10170719
    Abstract: A method for inorganic surface passivation in a photovoltaic device includes etching a native oxide over an inorganic substrate, the inorganic substrate having a surface; and forming an organic monolayer on the surface of the inorganic substrate to form a heterojunction, the organic monolayer having the following formula: ˜X—Y, wherein X is an oxygen or a sulfur; Y is an alkyl chain, an alkenyl chain, or an alkynyl chain; and X covalently bonds to the surface of the inorganic substrate by a covalent bond.
    Type: Grant
    Filed: December 10, 2015
    Date of Patent: January 1, 2019
    Assignee: INTERNATIONAL BUSINESS MACHINES CORPROATION
    Inventors: Ali Afzali-Ardakani, Bahman Hekmatshoartabari, Davood Shahrjerdi
  • Patent number: 10170720
    Abstract: A method for inorganic surface passivation in a photovoltaic device includes etching a native oxide over an inorganic substrate, the inorganic substrate having a surface; and forming an organic monolayer on the surface of the inorganic substrate to form a heterojunction, the organic monolayer having the following formula: ˜X—Y, wherein X is an oxygen or a sulfur; Y is an alkyl chain, an alkenyl chain, or an alkynyl chain; and X covalently bonds to the surface of the inorganic substrate by a covalent bond.
    Type: Grant
    Filed: November 21, 2017
    Date of Patent: January 1, 2019
    Assignee: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Ali Afzali-Ardakani, Bahman Hekmatshoartabari, Davood Shahrjerdi
  • Patent number: 10141461
    Abstract: A method for forming a multi-junction photovoltaic device includes providing a germanium layer and etching pyramidal shapes in the germanium layer such that (111) facets are exposed to form a textured surface. A first p-n junction is formed on or over the textured surface from III-V semiconductor materials. Another p-n junction is formed over the first p-n junction from III-V semiconductor materials and follows the textured surface.
    Type: Grant
    Filed: July 13, 2015
    Date of Patent: November 27, 2018
    Assignee: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Bahman Hekmatshoartabari, Ali Khakifirooz, Ghavam G. Shahidi, Davood Shahrjerdi
  • Publication number: 20180323330
    Abstract: A photovoltaic device that includes an upper cell that absorbs a first range of wavelengths of light and a bottom cell that absorbs a second range of wavelengths of light. The bottom cell includes a heterojunction comprising a crystalline germanium containing (Ge) layer. At least one surface of the crystalline germanium (Ge) containing layer is in contact with a silicon (Si) containing layer having a larger band gap than the crystalline (Ge) containing layer.
    Type: Application
    Filed: July 13, 2018
    Publication date: November 8, 2018
    Inventors: Keith E. Fogel, Bahman Hekmatshoartabari, Devendra K. Sadana, Ghavam G. Shahidi, Davood Shahrjerdi
  • Patent number: 10115773
    Abstract: Hybrid high electron mobility field-effect transistors including inorganic channels and organic gate barrier layers are used in some applications for forming high resolution active matrix displays. Arrays of such high electron mobility field-effect transistors are electrically connected to thin film switching transistors and provide high drive currents for passive devices such as organic light emitting diodes. The organic gate barrier layers are operative to suppress both electron and hole transport between the inorganic channel layer and the gate electrodes of the high electron mobility field-effect transistors.
    Type: Grant
    Filed: November 20, 2016
    Date of Patent: October 30, 2018
    Assignee: International Business Machines Corporation
    Inventors: Ali Afzali-Ardakani, Bahman Hekmatshoartabari, Devendra K. Sadana, Davood Shahrjerdi