Cadmium Containing Patents (Class 136/260)
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Patent number: 6025252Abstract: In order to easily and accurately manufacture a micromachine comprising a member which is made of a single-crystalline material and having a complicated structure, an uppermost layer (1104) of a single-crystalline Si substrate (1102) whose (100) plane is upwardly directed is irradiated with Ne atom currents from a plurality of prescribed directions, so that the crystal orientation of the uppermost layer (1104) is converted to such orientation that the (111) plane is upwardly directed. A masking member (106) is employed as a shielding member to anisotropically etch the substrate (1102) from its bottom surface, thereby forming a V-shaped groove (1112). At this time, the uppermost layer (1104) serves as an etching stopper. Thus, it is possible to easily manufacture a micromachine having a single-crystalline diaphragm having a uniform thickness. A micromachine having a complicated member such as a diagram which is made of a single-crystalline material can be easily manufactured through no junction.Type: GrantFiled: August 25, 1997Date of Patent: February 15, 2000Assignee: Mega Chips CorporationInventors: Masahiro Shindo, Daisuke Kosaka, Tetsuo Hikawa, Akira Takata, Yukihiro Ukai, Takashi Sawada, Toshifumi Asakawa
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Patent number: 6023020Abstract: A solar cell utilizing a chalcopyrite semiconductor and reducing the density of defects on the junction interface of pn junctions is provided. This solar cell includes a substrate, a back electrode formed on the substrate, a p-type chalcopyrite semiconductor thin film formed on the back electrode, an n-type semiconductor thin film formed so as to constitute a pn junction with the p-type chalcopyrite semiconductor thin film, and a transparent electrode formed on the n-type semiconductor thin film. A material having a higher resistivity than the p-type chalcopyrite semiconductor is formed between the p-type chalcopyrite semiconductor thin film and the n-type semiconductor thin film. A thin film made of this material may be formed by deposition from a solution. For example, CuInS.sub.2 is formed on the surface of a p-type chalcopyrite based semiconductor such as CuInSe.sub.Type: GrantFiled: October 14, 1997Date of Patent: February 8, 2000Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Mikihiko Nishitani, Takayuki Negami, Naoki Kohara, Takahiro Wada, Yasuhiro Hashimoto
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Patent number: 6015951Abstract: This invention relates to a photoelectric transfer device which comprises a photoelectric transfer element, a cholesteric liquid crystal layer and an ultraviolet cut-off layer, said cholesteric liquid crystal layer being arranged between said photoelectric transfer element and said ultraviolet cut-off layer and said ultraviolet cut-off layer being arranged at the side for the incidence of light. According to this invention, there is provided a colorful photoelectric transfer device which is prepared at an inexpensive cost without a marked decrease in the generation efficiency of the photoelectric transfer element and is fit to be used over a prolonged period.Type: GrantFiled: November 20, 1997Date of Patent: January 18, 2000Assignee: Nippon Oil Company, LimitedInventors: Keizo Ikai, Mitsuo Matsuno
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Patent number: 5994642Abstract: A method for forming a CdTe film of good quality by an improved close-spaced sublimation process is disclosed. This method comprises: a step of applying a paste which contains material for CdTe semiconductor on a supporting member, thereby to form a coating film which contains the material for the semiconductor on the surface of the supporting member; a step of closely arranging the supporting member and a substrate on which a CdTe film is to be formed, to make the coating film to face the surface of the substrate; and a step of forming a CdTe film on the substrate, by heating the coating film and the substrate, and causing the material for the semiconductor in the coating film to evaporate.Type: GrantFiled: March 13, 1998Date of Patent: November 30, 1999Assignee: Matsushita Battery Industrial Co., Ltd.Inventors: Hiroshi Higuchi, Seiji Kumazawa, Takashi Arita, Akira Hanafusa, Mikio Murozono, Tetsuya Aramoto
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Patent number: 5990415Abstract: A multilayer solar cell with bypass diodes includes a stack of alternating p and n type semiconductor layers 10, 11, 12, 13, 14 arranged to form a plurality of rectifying photovoltaic junctions 15, 16, 17, 18. Contact is made to underlying layers by way of a buried contact structure comprising grooves extending down through all of the active layers, the walls of each groove being doped 33, 34 with n-or p-type impurities depending upon the layers to which the respective contact is to be connected and the grooves being filled with metal contact material 31, 32. One or more bypass diodes are provided by increasing the doping levels on either side 10, 13 of one or more portions of the junctions 16 of the cell such that quantum mechanical tunnelling provides a reverse bias characteristic whereby conduction occurs under predetermined reverse bias conditions. Ideally, the doping levels in the bypass diodes is 10.sup.18 atoms/cm.sup.3 or greater and the junction area is small.Type: GrantFiled: May 29, 1997Date of Patent: November 23, 1999Assignee: Pacific Solar Pty LtdInventors: Martin Andrew Green, Stuart Ross Wenham
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Patent number: 5986205Abstract: The stainless steel sheet useful as a substrate for non-single crystalline semiconductor solar cells has minute ripples with undulations along a rolling direction, and its surface roughness is controlled in the range of R.sub.z 0.3-1.4 .mu.m and R.sub.max 0.5-1.7 .mu.m. It is manufactured by finish cold rolling a stainless steel strip with a reduction ratio of at least 20% at a rolling speed of at least 400 m/min. using work rolls polished with abrasives of gage #100-#400 at a final pass, annealing the rolled strip in an open-air atmosphere and then electrolytically pickling the annealed strip in a nitric acid solution. Since minute ripples with undulations are formed on the surface of the stainless steel sheet, an energy conversion efficiency is increased by acceleration of scattering and multiple reflection of incident light rays projected into a non-single crystalline semiconductor layer.Type: GrantFiled: September 4, 1997Date of Patent: November 16, 1999Assignees: Nisshin Steel Co., Ltd., Canon Kabushiki KaishaInventors: Hisashi Matsune, Yasushi Nishimura, Takuji Okiyama, Masafumi Sano
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Patent number: 5955772Abstract: A heterostructure thermionic cooler and a method for making thermionic coolers, employing a barrier layer of varying conduction bandedge for n-type material, or varying valence bandedge for p-type material, that is placed between two layers of material. The barrier layer has a high enough barrier for the cold side to only allow "hot" electrons, or electrons of high enough energy, across the barrier. The barrier layer is constructed to have an internal electric field such that the electrons that make it over the initial barrier are assisted in travel to the anode. Once electrons drop to the energy level of the anode, they lose energy to the lattice, thus heating the lattice at the anode. The barrier height of the barrier layer is high enough to prevent the electrons from traveling in the reverse direction.Type: GrantFiled: December 17, 1996Date of Patent: September 21, 1999Assignee: The Regents of the University of CaliforniaInventors: Ali Shakouri, John E. Bowers
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Patent number: 5922142Abstract: A photovoltaic device having a substrate, a layer of Cd.sub.2 SnO.sub.4 disposed on said substrate as a front contact, a thin film comprising two or more layers of semiconductor materials disposed on said layer of Cd.sub.2 SnO.sub.4, and an electrically conductive film disposed on said thin film of semiconductor materials to form a rear electrical contact to said thin film. The device is formed by RF sputter coating a Cd.sub.2 SnO.sub.4 layer onto a substrate, depositing a thin film of semiconductor materials onto the layer of Cd.sub.2 SnO.sub.4, and depositing an electrically conductive film onto the thin film of semiconductor materials.Type: GrantFiled: November 18, 1996Date of Patent: July 13, 1999Assignee: Midwest Research InstituteInventors: Xuanzhi Wu, Timothy J. Coutts, Peter Sheldon, Douglas H. Rose
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Patent number: 5868869Abstract: Provided is a thin film photovoltaic device and a method of manufacturing the device. The thin film photovoltaic device comprises a film layer having particles which are smaller than about 30 microns in size held in an electrically insulating matrix material to reduce the potential for electrical shorting through the film layer. The film layer may be provided by depositing preformed particles onto a surrogate substrate and binding the particles in a film-forming matrix material to form a flexible sheet with the film layer. The flexible sheet may be separated from the surrogate substrate and cut into flexible strips. A plurality of the flexible strips may be located adjacent to and supported by a common supporting substrate to form a photovoltaic module having a plurality of electrically interconnected photovoltaic cells.Type: GrantFiled: October 7, 1997Date of Patent: February 9, 1999Assignee: Photon Energy, Inc.Inventors: Scot P. Albright, Rhodes Chamberlin
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Patent number: 5738731Abstract: A solar cell comprising:a first junction part having a first conductivity type first semiconductor film and a second conductivity type second semiconductor film formed on an upper surface of said first semiconductor film; anda second junction part having a first conductivity type third semiconductor film formed on an upper surface of said second semiconductor film and a second conductivity type fourth semiconductor formed on an upper surface of said third semiconductor film,said junction parts arranged from that having a larger forbidden band width along the direction of progress of light through said semiconductor layers,said first, second, third, and fourth semiconductor films being formed of single-crystalline filming;wherein an interlayer conductor prepared from a metal forming ohmic junctions with each of said junction parts and having a thickness capable of transmitting light therethrough is interposed between said first and second junction parts; andwherein said second semiconductor film arranged on onType: GrantFiled: August 31, 1994Date of Patent: April 14, 1998Assignees: Mega Chips Corporation, Crystal Device CorporationInventors: Masahiro Shindo, Daisuke Kosaka, Tetsuo Hikawa, Akira Takata, Yukihiro Ukai, Takashi Sawada, Toshifumi Asakawa
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Patent number: 5731031Abstract: A process for chemical bath deposition of selenide and sulfide salts as films and powders employable as precursors for the fabrication of solar cell devices. The films and powders include (1) Cu.sub.x Se.sub.n, wherein x=1-2 and n=1-3; (2) Cu.sub.x Ga.sub.y Se.sub.n, wherein x=1-2, y=0-1 and n=1-3; (3) Cu.sub.x In.sub.y Se.sub.n, wherein x=1-2.27, y=0.72-2 and n=1-3; (4) Cu.sub.x (InGa).sub.y Se.sub.n, wherein x=1-2.17, y=0.96-2 and n=1-3; (5) In.sub.y Se.sub.n, wherein y=1-2.3 and n=1-3; (6) Cu.sub.x S.sub.n, wherein x=1-2 and n=1-3; and (7) Cu.sub.x (InGa).sub.y (SeS).sub.n, wherein x=1-2, y=0.07-2 and n=0.663-3.Type: GrantFiled: December 20, 1995Date of Patent: March 24, 1998Assignee: Midwest Research InstituteInventors: Raghu Nath Bhattacharya, Rommel Noufi, Li Wang
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Patent number: 5714391Abstract: This invention relates to a manufacturing method of a compound semiconductor thin film derived from a metal sulfide produced by thermal decomposition of a sulfur-containing metal organic compound, the compound containing at least one functional group having at least one metal atom selected from the group consisting of copper, zinc, cadmium, mercury, and lead, and the functional group also containing at least one sulfur atom. Since the obtained metal sulfides are of high-purity and dense, they can be utilized in various photoelectric devices. Particularly, the photoelectric conversion efficiency of a CdS/CdTe system thin film compound semiconductor solar cell can be improved remarkably by employing a layer made of a CdS thin film as a window of the solar cell.Type: GrantFiled: May 16, 1996Date of Patent: February 3, 1998Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Kuniyoshi Omura, Tsuyoshi Nishio, Satoshi Shibutani, Shigeo Kondoh, Mikio Murozono, Akira Hanafusa, Hideaki Oyama
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Patent number: 5712187Abstract: A method of depositing a semiconductor material on a substrate. The method sequentially comprises (a) providing the semiconductor material in a depositable state such as a vapor for deposition on the substrate; (b) depositing the semiconductor material on the substrate while heating the substrate to a first temperature sufficient to cause the semiconductor material to form a first film layer having a first grain size; (c) continually depositing the semiconductor material on the substrate while cooling the substrate to a second temperature sufficient to cause the semiconductor material to form a second film layer deposited on the first film layer and having a second grain size smaller than the first grain size; and (d) raising the substrate temperature, while either continuing or not continuing to deposit semiconductor material to form a third film layer, to thereby anneal the film layers into a single layer having favorable efficiency characteristics in photovoltaic applications.Type: GrantFiled: November 9, 1995Date of Patent: January 27, 1998Assignee: Midwest Research InstituteInventors: Xiaonan Li, Peter Sheldon
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Patent number: 5674325Abstract: Provided is a thin film photovoltaic device and a method of manufacturing the device. The thin film photovoltaic device comprises a film layer having particles which are smaller than about 30 microns in size held in an electrically insulating matrix material to reduce the potential for electrical shorting through the film layer. The film layer may be provided by depositing preformed particles onto a surrogate substrate and binding the particles in a film-forming matrix material to form a flexible sheet with the film layer. The flexible sheet may be separated from the surrogate substrate and cut into flexible strips. A plurality of the flexible strips may be located adjacent to and supported by a common supporting substrate to form a photovoltaic module having a plurality of electrically interconnected photovoltaic cells.Type: GrantFiled: June 7, 1995Date of Patent: October 7, 1997Assignee: Photon Energy, Inc.Inventors: Scot P. Albright, Rhodes Chamberlin
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Patent number: 5567469Abstract: A chalcopyrite compound, for instance, CuInS.sub.2 or CuInSe.sub.2, is prepared by subjecting a thin film containing copper metal, indium metal, and an indium compound or a compound which contains both indium and copper, selected from the group consisting of oxides, sulfides and selenides, with heat under a reducing atmosphere containing at least one of the Group VIb element or under an atmosphere containing a reducing compound of at least one of the Group VIb element, thereby converting said thin film into a chalcopyrite compound.Type: GrantFiled: June 1, 1995Date of Patent: October 22, 1996Assignee: Matsuhita Electric Co., Ltd.Inventors: Takahiro Wada, Mikihiko Nishitani, Takayuki Negami
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Patent number: 5565041Abstract: A polysilane composition containing conductor or semiconductor particles useful as a portion of a non-linear optical device.Type: GrantFiled: May 26, 1995Date of Patent: October 15, 1996Assignee: Kabushiki Kaisha ToshibaInventors: Toshiro Hiraoka, Shin-ichi Nakamura, Yoshihiko Nakano, Shinji Murai, Shuzi Hayase
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Patent number: 5541118Abstract: A process for producing a layer of cadmium sulfide on a cadmium telluride surface to be employed in a photovoltaic device. The process comprises providing a cadmium telluride surface which is exposed to a hydrogen sulfide plasma at an exposure flow rate, an exposure time and an exposure temperature sufficient to permit reaction between the hydrogen sulfide and cadmium telluride to thereby form a cadmium sulfide layer on the cadmium telluride surface and accomplish passivation. In addition to passivation, a heterojunction at the interface of the cadmium sulfide and the cadmium telluride can be formed when the layer of cadmium sulfide formed on the cadmium telluride is of sufficient thickness.Type: GrantFiled: May 22, 1995Date of Patent: July 30, 1996Assignee: Midwest Research InstituteInventors: Dean H. Levi, Art J. Nelson, Richard K. Ahrenkiel
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Patent number: 5538903Abstract: A method of manufacturing a solar cell, comprising the steps of forming a layer of n-type compound semiconductor, a layer of p-type compound semiconductor, and an electrode layer on a glass substrate, wherein at least one of said steps of forming a layer of compound semiconductor layer comprises preparing a paste by mixing a semiconductor raw material and a viscous agent, applying said paste to said substrate, drying said paste to harden it, and firing the dried paste, and vibrating said substrate during or after the application of the paste, to remove the bubbles in the paste, resulting in a semiconductor layer which is smooth, dense, and having good adhesion, thus realizing a solar cell with improved and uniform characteristics.Type: GrantFiled: November 18, 1994Date of Patent: July 23, 1996Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Tetsuya Aramoto, Nobuo Nakayama, Kuniyoshi Omura, Mikio Murozono
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Patent number: 5536333Abstract: A process and apparatus (70) for making a large area photovoltaic device (22) that is capable of generating low cost electrical power. The apparatus (70) for performing the process includes an enclosure (126) providing a controlled environment in which an oven (156) is located. At least one and preferably a plurality of deposition stations (74,76,78) provide heated vapors of semiconductor material within the oven (156) for continuous elevated temperature deposition of semiconductor material on a sheet substrate (24) including a glass sheet (26) conveyed within the oven. The sheet substrate (24) is conveyed on a roller conveyor (184) within the oven (156) and the semiconductor material whose main layer (82) is cadmium telluride is deposited on an upwardly facing surface (28) of the substrate by each deposition station from a location within the oven above the roller conveyor.Type: GrantFiled: August 15, 1995Date of Patent: July 16, 1996Assignee: Solar Cells, Inc.Inventors: James B. Foote, Steven A. F. Kaake, Peter V. Meyers, James F. Nolan
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Patent number: 5501744Abstract: A photovoltaic cell has an n-type polycrystalline layer and a p-type polycrystalline layer adjoining the n-type polycrystalline layer to form a photovoltaic junction. The p-type polycrystalline layer comprises a substantially planar layer portion having relatively large crystals adjoining the n-type polycrystalline layer. The planar layer portion includes oxidized impurities which contribute to obtainment of p-type electrical properties in the planar layer portion.Type: GrantFiled: July 12, 1994Date of Patent: March 26, 1996Assignee: Photon Energy, Inc.Inventors: Scot P. Albright, Rhodes R. Chamberlin
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Patent number: 5500056Abstract: A solar cell includes a compound semiconductor, which is a laminated film having compound semiconductor layers, and low melting point glass. When the solar cell is heated by fire, the low melting point glass melts to seal the compound semiconductor so that toxic substances contained in the compound semiconductor are not released into the air.Type: GrantFiled: July 18, 1994Date of Patent: March 19, 1996Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Takahiro Wada, Mitsusuke Ikeda, Mikihiko Nishitani, Masaharu Terauchi, Takayuki Negami, Naoki Kohara
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Patent number: 5484736Abstract: A process for producing a cadmium telluride polycrystalline film having grain sizes greater than about 20 .mu.m. The process comprises providing a substrate upon which cadmium telluride can be deposited and placing that substrate within a vacuum chamber containing a cadmium telluride effusion cell. A polycrystalline film is then deposited on the substrate through the steps of evacuating the vacuum chamber to a pressure of at least 10.sup.-6 torr.; heating the effusion cell to a temperature whereat the cell releases stoichiometric amounts of cadmium telluride usable as a molecular beam source for growth of grains on the substrate; heating the substrate to a temperature whereat a stoichiometric film of cadmium telluride can be deposited; and releasing cadmium telluride from the effusion cell for deposition as a film on the substrate.Type: GrantFiled: September 19, 1994Date of Patent: January 16, 1996Assignee: Midwest Research InstituteInventors: Falah S. Hasoon, Art J. Nelson
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Patent number: 5472910Abstract: Ohmic contacts to p-type IIB/VIB semiconductor are obtained by a process which includes the step of depositing a viscous liquid containing a Group IB metal salt on a surface of a semiconductor, substantially free of oxide groups, heating to form a dried layer, removing the dried layer, washing the surface to remove residual by-products and drying the surface.Type: GrantFiled: March 16, 1994Date of Patent: December 5, 1995Assignee: BP Solar LimitedInventors: Daniel R. Johnson, Sener Oktik, Mehmet E. Ozsan, Michael H. Patterson
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Patent number: 5470397Abstract: A process and apparatus (70) for making a large area photovoltaic device (22) that is capable of generating low cost electrical power. The apparatus (70) for performing the process includes an enclosure (126) providing a controlled environment in which an oven (156) is located. At least one and preferably a plurality of deposition stations (74,76,78) provide heated vapors of semiconductor material within the oven (156) for continuous elevated temperature deposition of semiconductor material on a sheet substrate (24) including a glass sheet (26) conveyed within the oven. The sheet substrate (24) is conveyed on a roller conveyor (184) within the oven (156) and the semiconductor material whose main layer (82) is cadmium telluride is deposited on an upwardly facing surface (28) of the substrate by each deposition station from a location within the oven above the roller conveyor.Type: GrantFiled: September 2, 1994Date of Patent: November 28, 1995Assignee: Solar Cells, Inc.Inventors: James B. Foote, Steven A. F. Kaake, Peter V. Meyers, James F. Nolan
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Patent number: 5436204Abstract: A process for fabricating slightly Cu-poor thin-films of Cu(In,Ga)Se.sub.2 on a substrate for semiconductor device applications includes the steps of forming initially a slightly Cu-rich, phase separated, mixture of Cu(In,Ga)Se.sub.2 :Cu.sub.x Se on the substrate in solid form followed by exposure of the Cu(In,Ga)Se.sub.2 :Cu.sub.x Se solid mixture to an overpressure of Se vapor and (In,Ga) vapor for deposition on the Cu(In,Ga)Se.sub.2 :Cu.sub.x Se solid mixture while simultaneously increasing the temperature of the solid mixture toward a recrystallization temperature (about 550.degree. C.) at which Cu(In,Ga)Se.sub.2 is solid and Cu.sub.x Se is liquid. The (In,Ga) flux is terminated while the Se overpressure flux and the recrystallization temperature are maintained to recrystallize the Cu.sub.x Se with the (In, Ga) that was deposited during the temperature transition and with the Se vapor to form the thin-film of slightly Cu-poor Cu.sub.x (In,Ga).sub.y Se.sub.z.Type: GrantFiled: August 22, 1994Date of Patent: July 25, 1995Assignee: Midwest Research InstituteInventors: David S. Albin, Jeffrey J. Carapella, John R. Tuttle, Miguel A. Contreras, Andrew M. Gabor, Rommel Noufi, Andrew L. Tennant
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Patent number: 5411601Abstract: A solar cell is constructed using a heterojunction formed by layering an n-type compound semiconductor followed by a p-type compound semiconductor on an insulator layer containing titanium oxide which has been formed on one side of a glass plate. The insulator layer can improve the photoelectric conversion efficiency of the solar cell by lowering the sheet resistance of the n-type semiconductor film which is used as the window material of the solar cell. In addition, light transmittance is improved.Type: GrantFiled: November 2, 1993Date of Patent: May 2, 1995Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Hiroshi Higuchi, Takashi Arita, Sotoyuki Kitamura, Mikio Murozono
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Patent number: 5393675Abstract: A thin film photovoltaic cell having a semiconductor layer of cadmium sulfide and a semiconductor layer of cadmium telluride is manufactured in a process in which the cadmium sulfide and the cadmium telluride are deposited onto a conductive layer of a substrate by RF sputtering. A layer of cadmium sulfide is deposited on the conducting layer of the substrate by RF magnetron sputtering. After the cadmium sulfide is deposited, a layer of cadmium telluride is deposited by RF magnetron sputtering. The RF sputtering deposition of the two semiconductor layers increases the efficiency of the cell and is conducive to a large scale manufacturing process. The photovoltaic cell may include only two semiconductor layers forming a p-n junction. A third semiconductor layer, typically zinc telluride, may be added to the cell to form a p-i-n junction. The efficiency of the cell is further increased by treatment with cadmium chloride and annealing in dry air.Type: GrantFiled: May 10, 1993Date of Patent: February 28, 1995Assignee: The University of ToledoInventor: Alvin D. Compaan
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Patent number: 5356839Abstract: Enhanced quality thin films of Cu.sub.w (In,Ga.sub.y)Se.sub.z for semiconductor device applications are fabricated by initially forming a Cu-rich, phase-separated compound mixture comprising Cu(In,Ga):Cu.sub.x Se on a substrate to form a large-grain precursor and then converting the excess Cu.sub.x Se to Cu(In,Ga)Se.sub.2 by exposing it to an activity of In and/or Ga, either in vapor In and/or Ga form or in solid (In,Ga).sub.y Se.sub.z. Alternatively, the conversion can be made by sequential deposition of In and/or Ga and Se onto the phase-separated precursor. The conversion process is preferably performed in the temperature range of about 300.degree.-600.degree. C., where the Cu(In,Ga)Se.sub.2 remains solid, while the excess Cu.sub.x Se is in a liquid flux. The characteristic of the resulting Cu.sub.w (In,Ga).sub.y Se.sub.z can be controlled by the temperature. Higher temperatures, such as 500.degree.-600.degree. C., result in a nearly stoichiometric Cu(In,Ga)Se.sub.Type: GrantFiled: April 12, 1993Date of Patent: October 18, 1994Assignee: Midwest Research InstituteInventors: John R. Tuttle, Miguel A. Contreras, Rommel Noufi, David S. Albin
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Patent number: 5304499Abstract: A method of making pn CdTe/CdS thin film solar cells, in which a transparent TCO layer is deposited as a front contact on a transparent substrate in the form of inexpensive soda-lime glass, and is preferably provided with an ultra-thin indium layer, which is in turn coated with the CdS layer, wherein the thus coated substrate is brought to the CdTe coating at a temperature between 480.degree. C. and 520.degree. C., which is maintained during the ensuing rapid CdTe deposition using the close-spaced sublimation method with a preferred rate of deposition of 5 to 15 .mu.m/min in an inert atmosphere. The indium layer dissolves during this deposition and effects the necessary n-doping of the CdS layer, without an additional method step. Solar cells can be made in this way with high efficiency in an inexpensive method, suitable for mass production.Type: GrantFiled: September 28, 1992Date of Patent: April 19, 1994Assignee: Battelle-Institut e.V.Inventors: Dieter Bonnet, Beate Henrichs, Karlheinz Jager, Hilmar Richter
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Patent number: 5279678Abstract: An improved photovoltaic panel and method of forming a photovoltaic panel are disclosed for producing a high efficiency CdS/CdTe photovoltaic cell. The photovoltaic panel of the present invention is initially formed with a substantially thick Cds layer, and the effective thickness of the CdS layer is substantially reduced during regrowth to both form larger diameter CdTe crystals and substantially reduce the effective thickness of the CThis invention was made with Government support under Subcontract No. ZL-7-06031-3 awarded by the Department of Energy. The Government has certain rights in this invention.Type: GrantFiled: January 13, 1992Date of Patent: January 18, 1994Assignee: Photon Energy, Inc.Inventors: John F. Jordan, Scot P. Albright
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Patent number: 5261968Abstract: An improved photovoltaic panel and method of forming a photovoltaic panel are disclosed for producing a high efficiency CdS/CdTe photovoltaic cell. The photovoltaic panel of the present invention is initially formed with a substantially thick CdS layer, and the effective thickness of the CdS layer is substantially reduced during regrowth to both form large diameter CdTe crystals and substantially reduce the effective thickness of the CdS layer by diffusion into the CdTe layer such that a majority of sunlight having a wavelength less than 520 nm passes through the CdS layer to the photovoltaic junction. Shorting of individual cells is substantially minimized by providing a conductive layer which is formed from two tin oxide layers, each having substantially dissimilar electrical conductivity, such that an electrically-conductive tin oxide layer interconnects the plurality of photovoltaic cells, while the comparatively high resistivity tin oxide layer prevents shorting of a cell.Type: GrantFiled: January 13, 1992Date of Patent: November 16, 1993Assignee: Photon Energy, Inc.Inventor: John F. Jordan
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Patent number: 5248349Abstract: A process and apparatus (70) for making a large area photovoltaic device (22) that is capable of generating low cost electrical power. The apparatus (70) for performing the process includes an enclosure (126) providing a controlled environment in which an oven (156) is located. At least one and preferably a plurality of deposition stations (74,76,78) provide heated vapors of semiconductor material within the oven (156) for continuous elevated temperature deposition of semiconductor material on a sheet substrate (24) including a glass sheet (26) conveyed within the oven. The sheet substrate (24) is conveyed on a roller conveyor (184) within the oven (156) and the semiconductor material whose main layer (82) is cadmium telluride is deposited on an upwardly facing surface (28) of the substrate by each deposition station from a location within the oven above the roller conveyor.Type: GrantFiled: May 12, 1992Date of Patent: September 28, 1993Assignee: Solar Cells, Inc.Inventors: James B. Foote, Steven A. F. Kaake, Peter V. Meyers, James F. Nolan
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Patent number: 5141564Abstract: A thin film heterojunction solar cell and a method of making it has a p-type layer of mixed ternary I-III-VI.sub.2 semiconductor material in contact with an n-type layer of mixed binary II-VI semiconductor material. The p-type semiconductor material includes a low resistivity copper-rich region adjacent the back metal contact of the cell and a composition gradient providing a minority carrier mirror that improves the photovoltaic performance of the cell. The p-type semiconductor material preferably is CuInGaSe.sub.2 or CuIn(SSe).sub.2.Type: GrantFiled: January 17, 1991Date of Patent: August 25, 1992Assignee: The Boeing CompanyInventors: Wen S. Chen, John M. Stewart
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Patent number: 5112410Abstract: A process for depositing thin layers of a II-VI compound cadmium zinc sulfide (CdZnS) by an aqueous solution growth technique with quality suitable for high efficiency photovoltaic or other devices which can benefit from the band edge shift resulting from the inclusion of Zn in the sulfide. A first solution comprising CdCl.sub.2 2.5H.sub.2 O, NH.sub.4 Cl, NH.sub.4 OH and ZnCl.sub.2, and a second solution comprising thiourea ((NH.sub.2).sub.2 CS) are combined and placed in a deposition cell, along with a substrate to form a thin i.e. 10 nm film of CdZnS on the substrate. This process can be sequentially repeated with to achieve deposition of independent multiple layers having different Zn concentrations.Type: GrantFiled: August 7, 1990Date of Patent: May 12, 1992Assignee: The Boeing CompanyInventor: Wen S. Chen
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Patent number: 5078804Abstract: A thin film I-III-VI.sub.2 based solar cell having a first layer of copper indium gallium selenide, a second layer of cadmium zinc sulfide, a double layer of zinc oxide, and a metallization structure comprised of a layer of nickel covered by a layer of aluminum. An optional antireflective coating may be placed on said metallization structure. The cadmium zinc sulfide layer is deposited by means of an aqueous solution growth deposition process and may actually consist of two layers: a low zinc content layer and a high zinc content layer. Photovoltaic efficiencies of 12.5% at Air Mass 1.5 illumination conditions and 10.4% under AMO illumination can be achieved.Type: GrantFiled: August 17, 1990Date of Patent: January 7, 1992Assignee: The Boeing CompanyInventors: Wen S. Chen, John M. Stewart
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Patent number: 5078803Abstract: Transparent conductors for use in a variety of different photovoltaic devices are disclosed, comprising at least one ZnO transparent conductor layer having a predetermined level of haziness achieved, e.g., through appropriate variation in the parameters employed in formation of the transparent conductor (for example, by chemical vapor deposition) and/or through treatment of the transparent conductor subsequent to its formation. The concentration and/or relative rate of introduction of dopant during the deposition of the transparent conductor may be adjusted to prepare films having the desired morphology and/or structure. Alternatively, the morphology, composition and/or structure of the transparent conductor may be modified by suitable post-formation treatments. A combination of at least two transparent layers may also be employed, comprising at least a first layer designed primarily to maximize the optical properties and at least a second layer designed to maximize the electrical properties.Type: GrantFiled: September 22, 1989Date of Patent: January 7, 1992Assignee: Siemens Solar Industries L.P.Inventors: David N. Pier, Charles F. Gay, Robert D. Wieting, Heidi J. Langeberg
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Patent number: 5028274Abstract: This invention relates to an improved thin film solar cell with excellent electrical and mechanical integrity. The device comprises a substrate, a Group I-III-VI.sub.2 semiconductor absorber layer and a transparent window layer. The mechanical bond between the substrate and the Group I-III-VI.sub.2 semiconductor layer is enhanced by an intermediate layer between the substrate and the Group I-III-VI.sub.2 semiconductor film being grown. The intermediate layer contains tellurium or substitutes therefor, such as Se, Sn, or Pb. The intermediate layer improves the morphology and electrical characteristics of the Group I-III-VI.sub.2 semiconductor layer.Type: GrantFiled: June 7, 1989Date of Patent: July 2, 1991Assignee: International Solar Electric Technology, Inc.Inventors: Bulent M. Basol, Vijay K. Kapur
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Patent number: 4959106Abstract: A photovoltaic element which generates photoelectromotive force by the contact of a p-type semiconductor layer and an n-type semiconductor layer, characterized in that at least one of said semiconductor layers is made up from a deposited film composed of zinc atoms, selenium atoms, optional tellurium atoms, and at least hydrogen atoms, said deposited film containing a p-type or n-type doping agent, containing 1 to 4 atomic % of hydrogen atoms, containing selenium atoms and tellurium atoms in a ratio of 1:9 to 3:7 (in terms of number of atoms), and also containing crystal grains in a ratio of 65 to 85 vol % per unit volume.Type: GrantFiled: August 28, 1989Date of Patent: September 25, 1990Assignee: Canon Kabushiki KaishaInventors: Katsumi Nakagawa, Masahiro Kanai, Shunichi Ishihara, Kozo Arao, Yasushi Fujioka, Akira Sakai, Tsutomu Murakami
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Patent number: 4915745Abstract: A structure for, and method of making, thin films of Group I-III-VI compound semiconductors such as copper indium diselenide for use in heterojunction photovoltaic devices fabricated on metal substrates. An interfacial film containing gallium is first deposited upon the substrate. Thereafter, copper and indium films are deposited and the resulting stacked film is heated in the presence of a source of selenium to form copper indium diselenide semiconductor material with improved adhesion to the substrate and improved performance.Type: GrantFiled: September 22, 1988Date of Patent: April 10, 1990Assignee: Atlantic Richfield CompanyInventors: Gary A. Pollock, Kim W. Mitchell, James H. Ermer
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Patent number: 4909857Abstract: A method of electrodepositing a doped compound semiconductor film including tellurium and a metal selected from Group IIB of the Period Table of Elements by adding an effective concentration of dopant ions to the electrolyte bath. Cadmium telluride, mercury cadmium telluride and zinc cadmium telluride may be doped with copper, silver and gold. The conductivity type of the electrodeposited doped layers may be changed by a heat treatment. Thin film photovoltaic cells incorporating the doped layer to form a heterojunction with a semiconductor layer of the opposite conductivity type show substantial improvements in open circuit voltage, fill factor and efficiency over similar devices employing undoped electrodeposited layers.Type: GrantFiled: December 21, 1988Date of Patent: March 20, 1990Assignee: Standard Oil CompanyInventors: Miroslav Ondris, Marty A. Pichler, Richard E. Brownfield
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Patent number: 4888062Abstract: An improved pin junction photovoltaic element which generates photoelectromotive force by the junction of a p-type semiconductor layer, an i-type semiconductor layer and an n-type semiconductor layer, characterized in that at least said i-type semiconductor layer comprises a member selected from the group consisting of a ZnSe:H deposited film containing the hydrogen atoms in an amount of 1 to 4 atomic % and crystal grain domains in a proportion of 65 to 85 vol % per unit volume and a ZnSe.sub.1-x Te.sub.x :H deposited film containing the hydrogen atoms in an amount of 1 to 4 atomic % and crystal grain domains in a proportion of 65 to 85 vol % per unit volume and also containing the selenium atoms and the tellurium atoms in a Se/Te quantitative ratio of 1:9 to 3:7.The pin junction photovoltaic element exhibits an improved photoelectric conversion efficiency for short-wavelength light and has a high open-circuit voltage.Type: GrantFiled: August 26, 1988Date of Patent: December 19, 1989Assignee: Canon Kabushiki KaishaInventors: Katsumi Nakagawa, Masahiro Kanai, Shunichi Ishihara, Kozo Arao, Yasushi Fujioka, Akira Sakai, Tsutomu Murakami
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Patent number: 4873198Abstract: A method of making a multi-layer photovoltaic cell containing a heat-treated layer including Cd and Te, comprising the sequential steps of applying a chloride to the layer, heat-treating the layer with the chloride thereon, and subsequently depositing another semiconductor layer thereon.Type: GrantFiled: June 2, 1988Date of Patent: October 10, 1989Assignee: Ametek, Inc.Inventors: Peter V. Meyers, Chung-Heng Liu, Timothy J. Frey
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Patent number: 4828875Abstract: Sintered films of Cd.sub.1-x Zn.sub.x S (0.ltoreq.x<1) with high optical transmittance are provided. These films are produced by applying a paste composed of powdered CdS and CdCl.sub.2 or of a mixture of CdS, ZnS and CdCl.sub.2 onto an appropriate substrate such as borosilicate glass, under an inert gas atmosphere containing ZnCl.sub.2 vapor or thereafter resintering the paste on the substrate under a nitrogen atmosphere.The ZnCl.sub.2 vapor is produced by heating ZnCl.sub.2 at 400.degree. C. or higher but below the temperature of 500.degree.-700.degree. C. to which the specimen is heated.The resulting sintered films have optical transmittance of 80% at long wavelength ranges or higher and can be used as a window layer having a superior optical transmittance in solar cells.Type: GrantFiled: March 18, 1988Date of Patent: May 9, 1989Assignee: Korea Advanced Institute of Science & Tech.Inventors: Ho-Bin Im, Kyu-Charn Park
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Patent number: 4816120Abstract: A method of electrodepositing a doped compound semiconductor film including tellurium and a metal selected from Group IIB of the Period Table of Elements by adding an effective concentration of dopant ions to the electrolyte bath. Cadmium telluride, mercury cadmium telluride and zinc cadmium telluride may be doped with copper, silver and gold. The conductivity type of the electrodeposited doped layers may be changed by a heat treatment. Thin film photovoltaic cells incorporating the doped layer to form a heterojunction with a semiconductor layer of the opposite conductivity type show substantial improvements in open circuit voltage, fill factor and efficiency over similar devices employing undoped electrodeposited layers.Type: GrantFiled: January 26, 1988Date of Patent: March 28, 1989Assignee: The Standard Oil CompanyInventors: Miroslav Ondris, Marty A. Pichler, Richard E. Brownfield
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Patent number: 4812416Abstract: In order to be able to check whether or not a glow procedure is executed properly, i.e. reproducibly, the temporal course of the formation of characteristic stable reaction products is traced mass spectrometrically.Type: GrantFiled: November 28, 1986Date of Patent: March 14, 1989Inventors: Gerd Hewig, Berthold Schum, Jorg Worner
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Patent number: 4759951Abstract: A process for producing a photoelectric conversion film comprising heat-treating a coating (A) of a photoconductive material composed chiefly of at least one of CdSe, CdS, CdTe, CdS.sub.x Se.sub.1-x and CdS.sub.x Te.sub.1-x wherein x is a real number of less than 1, opposite from a coating (B) in proximity thereto, the coating (B) being made of a material composed chiefly of CdS and a Cd halide.Type: GrantFiled: September 23, 1986Date of Patent: July 26, 1988Assignee: Sharp Kabushiki KaishaInventors: Masataka Itoh, Masaya Nagata, Shuhei Tsuchimoto, Atsushi Yoshinouchi, Hiroshi Wada, Katsushi Okibayashi, Soji Ohhara
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Patent number: 4753684Abstract: A three layer, photovoltaic structure having polycrystalline semiconductor layers disposed in series optically and in sequential touching contact includes a relatively wide optical bandgap energy window layer, a light-absorbing layer and a third, relatively wide bandgap energy layer that forms a minority carrier mirror with the light-absorbing layer. All three layers have different compositions so that the structure includes two heterojunctions. The light-absorbing layer and third layer are of the same conductivity type. The structure is conveniently realized using II-VI semiconductor compounds such as a cadmium sulfide or zinc sulfide window layer, a mercury cadmium telluride, cadmium telluride, zinc cadmium telluride or mercury zinc telluride light-absorbing layer and a third layer of cadmium telluride, zinc telluride, zinc cadmium telluride, mercury cadmium telluride or cadmium manganese telluride. Cadmium is present in at least two of the three layers of the novel structures.Type: GrantFiled: October 31, 1986Date of Patent: June 28, 1988Assignee: The Standard Oil CompanyInventors: Miroslav Ondris, Marty A. Pichler
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Patent number: 4735662Abstract: A stable ohmic contact for thin films of p-type tellurium-containing II-VI semiconductors and photovoltaic devices incorporating such contacts. An ohmic contact according to the invention includes a contact-forming layer deposited on a p-type thin film of a tellurium-contacting II-VI semiconductor. Preferably, the contact-forming layer is copper having a thickness of about 2 nanometers. An isolation layer is deposited on the contact-forming to isolate subsequently deposited layers from the thin film. The isolation layer may be carbon or a thin layer of nickel. A connection layer for attaching an external electrical conductor is deposited on the isolation layer. The connection layer may be aluminum, chromium or a layer of copper, provided a copper layer is covered with one of silver, aluminum or a thin layer of nickel, preferably covered with aluminum.Type: GrantFiled: January 6, 1987Date of Patent: April 5, 1988Assignee: The Standard Oil CompanyInventors: Louis F. Szabo, William J. Biter
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Patent number: 4735909Abstract: Improved techniques are provided for forming a very thin polycrystalline layer of a semiconductor material on a glass substrate. The film material may be formed from a slurry of a semiconductor powder and a liquid carrier, and the slurry economically applied at room temperature by spraying techniques. Once dried, the film is compressed by the application of a substantial mechanical force. The compressed film is regrown in a heated atmosphere, forming a polycrystalline film comprised of large mean diameter crystals, with many crystals having a mean diameter in excess of the film thickness. A high quality cadmium sulfide polycrystalline film suitable for forming a photovoltaic cells may be inexpensively manufactured according to these techniques.Type: GrantFiled: October 14, 1986Date of Patent: April 5, 1988Assignee: Photon Energy, Inc.Inventors: Scot P. Albright, David K. Brown, John F. Jordon
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Patent number: 4734381Abstract: A phosphorous doped layer of cadmium telluride is deposited onto a conductive window layer to form a thin film cadmium telluride solar cell. Back contacts to the solar cell are made by first depositing a layer of p conductivity type lead telluride upon the cadmium telluride and then depositing the metallic back contacts onto the lead telluride.Type: GrantFiled: October 14, 1986Date of Patent: March 29, 1988Assignee: Atlantic Richfield CompanyInventor: Kim W. Mitchell