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).
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Patent number: 10541343Abstract: 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: GrantFiled: August 12, 2016Date of Patent: January 21, 2020Assignee: International Business Machines CorporationInventors: Stephen W. Bedell, Bahman Hekmatshoartabari, Devendra K. Sadana, Ghavam G. Shahidi, Davood Shahrjerdi
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Publication number: 20190288146Abstract: A solar cell having n-type and p-type interdigitated back contacts (IBCs), which cover the entire back surface of the absorber layer. The spatial separation of the IBCs is in a direction perpendicular to the back surface, thus providing borderless contacts having a zero-footprint separation. As the contacts are on the back, photons incident on the cell's front surface can be absorbed without any shadowing.Type: ApplicationFiled: June 3, 2019Publication date: September 19, 2019Applicant: International Business Machines CorporationInventors: Joel P. De Souza, Harold John Hovel, Daniel Inns, Jeehwan Kim, Christian Lavoie, Devendra K. Sadana, Katherine L. Saenger, Davood Shahrjerdi, Zhen Zhang
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Publication number: 20190279946Abstract: A method for making a photovoltaic device is provided that includes the steps of providing a silicon substrate having a complementary metal-oxide semiconductor (“CMOS”); bonding a first layer of silicon oxide to a second layer of silicon oxide wherein the bonded layers are deposited on the silicon substrate; and forming a III-V photovoltaic cell on a side of the bonded silicon oxide layers opposite the silicon substrate, wherein when the III-V photovoltaic cell is exposed to radiation, the III-V photovoltaic cell generates a current that powers a memory erasure device to cause an alteration of a memory state of a memory cell in an integrated circuit.Type: ApplicationFiled: May 23, 2019Publication date: September 12, 2019Inventors: Kenneth Rodbell, Davood Shahrjerdi
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Patent number: 10396229Abstract: A solar cell having n-type and p-type interdigitated back contacts (IBCs), which cover the entire back surface of the absorber layer. The spatial separation of the IBCs is in a direction perpendicular to the back surface, thus providing borderless contacts having a zero-footprint separation. As the contacts are on the back, photons incident on the cell's front surface can be absorbed without any shadowing.Type: GrantFiled: May 9, 2011Date of Patent: August 27, 2019Assignee: International Business Machines CorporationInventors: Joel P. De Souza, Harold J. Hovel, Daniel A. Inns, Jeehwan Kim, Christian Lavoie, Devendra K. Sadana, Katherine L. Saenger, Davood Shahrjerdi, Zhen Zhang
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Patent number: 10388815Abstract: A photovoltaic device and method include a crystalline substrate and an emitter contact portion formed in contact with the substrate. A back-surface-field junction includes a homogeneous junction layer formed in contact with the crystalline substrate and having a same conductivity type and a higher active doping density than that of the substrate. The homogeneous junction layer includes a thickness less than a diffusion length of minority carriers in the homogeneous junction layer. A passivation layer is formed in contact with the homogeneous junction layer opposite the substrate, which is either undoped or has the same conductivity type as that of the substrate.Type: GrantFiled: April 30, 2018Date of Patent: August 20, 2019Assignee: International Business Machines CorporationInventors: Tze-Chiang Chen, Bahman Hekmatshoartabari, Devendra K. Sadana, Davood Shahrjerdi
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Patent number: 10388814Abstract: Photovoltaic devices including direct gap III-V absorber materials and operatively associated back structures enhance efficiency by enabling photon recycling. The back structures of the photovoltaic devices include wide bandgap III-V layers, highly doped (In)GaAs layers, patterned oxide layers and metal reflectors that directly contact the highly doped (In)GaAs layers through vias formed in the back structures. Localized ohmic contacts are formed in the back structures of the devices.Type: GrantFiled: June 10, 2017Date of Patent: August 20, 2019Assignee: International Business Machines CorporationInventors: Bahman Hekmatshoartabari, Ali Khakifirooz, Ghavam G. Shahidi, Davood Shahrjerdi
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Publication number: 20190237511Abstract: 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: ApplicationFiled: April 6, 2019Publication date: August 1, 2019Inventors: Ali Afzali-Ardakani, Bahman Hekmatshoartabari, Devendra K. Sadana, Davood Shahrjerdi
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Publication number: 20190198696Abstract: 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: ApplicationFiled: February 26, 2019Publication date: June 27, 2019Inventors: Stephen W. Bedell, Keith E. Fogel, Bahman Hekmatshoar-Tabari, Devendra K. Sadana, Ghavam G. Shahidi, Davood Shahrjerdi
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Patent number: 10312400Abstract: 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: GrantFiled: October 18, 2016Date of Patent: June 4, 2019Assignee: International Business Machines CorporationInventors: Anirban Basu, Bahman Hekmatshoartabari, Davood Shahrjerdi
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Patent number: 10304985Abstract: 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: GrantFiled: May 20, 2015Date of Patent: May 28, 2019Assignee: International Business Machines CorporationInventors: Stephen W. Bedell, Keith E. Fogel, Bahman Hekmatshoar-Tabari, Devendra K. Sadana, Ghavam G. Shahidi, Davood Shahrjerdi
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Patent number: 10304944Abstract: 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: GrantFiled: July 18, 2016Date of Patent: May 28, 2019Assignee: International Business Machines CorporationInventors: Kangguo Cheng, Wilfried E. Haensch, Ali Khakifirooz, Davood Shahrjerdi
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Patent number: 10304984Abstract: 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: GrantFiled: September 7, 2012Date of Patent: May 28, 2019Assignee: International Business Machines CorporationInventors: Stephen W. Bedell, Keith E. Fogel, Bahman Hekmatshoar-Tabari, Devendra K. Sadana, Ghavam G. Shahidi, Davood Shahrjerdi
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Patent number: 10304986Abstract: 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: GrantFiled: June 14, 2017Date of Patent: May 28, 2019Assignee: INTERNATIONAL BUSINESS MACHINES CORPORATIONInventors: Bahman Hekmatshoar-Tabari, Devendra K. Sadana, Ghavam G. Shahidi, Davood Shahrjerdi
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Publication number: 20190157488Abstract: 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: ApplicationFiled: January 6, 2019Publication date: May 23, 2019Inventors: Bahman Hekmatshoartabari, Devendra K. Sadana, Wilfried E. Haensch, Ghavam G. Shahidi, Davood Shahrjerdi
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Patent number: 10283663Abstract: 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: GrantFiled: June 10, 2016Date of Patent: May 7, 2019Assignee: INTERNATIONAL BUSINESS MACHINES CORPORATIONInventors: Keith E. Fogel, Bahman Hekmatshoartabari, Devendra K. Sadana, Ghavam G. Shahidi, Davood Shahrjerdi
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Publication number: 20190123230Abstract: 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: ApplicationFiled: December 12, 2018Publication date: April 25, 2019Inventors: Bahman Hekmatshoar-Tabari, Devendra K. Sadana, Ghavam G. Shahidi, Davood Shahrjerdi
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Patent number: 10256357Abstract: 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: GrantFiled: November 14, 2017Date of Patent: April 9, 2019Assignee: International Business Machines CorporationInventors: Stephen W. Bedell, Bahman Hekmatshoartabari, Devendra K. Sadana, Ghavam G. Shahidi, Davood Shahrjerdi
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Patent number: 10256276Abstract: 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: GrantFiled: October 24, 2016Date of Patent: April 9, 2019Assignee: International Business Machines CorporationInventors: Ali Afzali-Ardakani, Bahman Hekmatshoartabari, Devendra K. Sadana, Davood Shahrjerdi
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Patent number: 10256363Abstract: 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: GrantFiled: October 25, 2017Date of Patent: April 9, 2019Assignee: International Business Machines CorporationInventors: Ning Li, Devendra K. Sadana, Davood Shahrjerdi
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Patent number: 10199524Abstract: 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: GrantFiled: January 13, 2012Date of Patent: February 5, 2019Assignee: International Business Machines CorporationInventors: Bahman Hekmatshoartabari, Devendra K. Sadana, Wilfried E. Haensch, Ghavam G. Shahidi, Davood Shahrjerdi