Abstract: A lattice-matched solar cell having a dilute nitride-based sub-cell has exponential doping to thereby control current-carrying capacity of the solar cell. Specifically a solar cell with at least one dilute nitride sub-cell that has a variably doped base or emitter is disclosed. In one embodiment, a lattice matched multi junction solar cell has an upper sub-cell, a middle sub-cell and a lower dilute nitride sub-cell, the lower dilute nitride sub-cell having doping in the base and/or the emitter that is at least partially exponentially doped so as to improve its solar cell performance characteristics. In construction, the dilute nitride sub-cell may have the lowest bandgap and be lattice matched to a substrate, the middle cell typically has a higher bandgap than the dilute nitride sub-cell while it is lattice matched to the dilute nitride sub-cell.

Abstract: Compound semiconductor alloys comprising dilute nitride materials, are materials used in absorbing layers for photodetectors, power converters, solar cells, and in particular to high efficiency, electronic and optoelectronic devices, including multijunction solar cells, photodetectors, power converters, and the like, formed primarily of III-V semiconductor alloys. The absorbing (or active) layers achieve improved characteristics including band gap optimization and minimization of defects.

Abstract: This disclosure relates to semiconductor devices and methods for fabricating semiconductor devices. Particularly, the disclosure relates to back-contact-only multijunction solar cells and the process flows for making such solar cells, including a wet etch process that removes semiconductor materials non-selectively without major differences in etch rates between heteroepitaxial III-V semiconductor layers.

Abstract: An alloy composition for a subcell of a solar cell is provided that has a bandgap of at least 0.9 eV, namely, Ga1-xInxNyAs1-y-zSbz with a low antimony (Sb) content and with enhanced indium (In) content and enhanced nitrogen (N) content, achieving substantial lattice matching to GaAs and Ge substrates and providing both high short circuit currents and high open circuit voltages in GaInNAsSb subcells for multijunction solar cells. The composition ranges for Ga1-xInxNyAs1-y-zSbz are 0.07?x?0.18, 0.025?y?0.04 and 0.001?z?0.03.

Abstract: Photovoltaic cells, methods for fabricating surface mount multijunction photovoltaic cells, methods for assembling solar panels, and solar panels comprising photovoltaic cells are disclosed. The surface mount multijunction photovoltaic cells include through-wafer-vias for interconnecting the front surface epitaxial layer to a contact pad on the back surface. The through-wafer-vias are formed using a wet etch process that removes semiconductor materials non-selectively without major differences in etch rates between heteroepitaxial III-V semiconductor layers.

Abstract: A single-step wet etch process is provided to isolate multijunction solar cells on semiconductor substrates, wherein the wet etch chemistry removes semiconductor materials nonselectively without a major difference in etch rate between different heteroepitaxial layers. The solar cells thus formed comprise multiple heterogeneous semiconductor layers epitaxially grown on the semiconductor substrate.

Abstract: A multi junction solar cell is provided with a non-alloyed ohmic contact metallization stack by inversion of the top semiconductor layer from n-type to p-type and including the utilization of a tunnel junction. Alternatively, the non-alloyed ohmic contact can be achieved by changing the top semiconductor layer from a higher bandgap material to a lower bandgap material.

Abstract: A single-step wet etch process is provided to isolate multijunction solar cells on semiconductor substrates, wherein the wet etch chemistry removes semiconductor materials nonselectively without a major difference in etch rate between different heteroepitaxial layers. The solar cells thus formed comprise multiple heterogeneous semiconductor layers epitaxially grown on the semiconductor substrate.

Abstract: An alloy composition for a subcell of a solar cell is provided that has a bandgap of at least 0.9 eV, namely, Ga1-xInxNyAs1-y-zSbz with a low antimony (Sb) content and with enhanced indium (In) content and enhanced nitrogen (N) content, achieving substantial lattice matching to GaAs and Ge substrates and providing both high short circuit currents and high open circuit voltages in GaInNAsSb subcells for multijunction solar cells. The composition ranges for Ga1-xInxNyAs1-y-zSbz are 0.07?x?0.18, 0.025?y?0.04 and 0.001?z?0.03.

Abstract: A package for a solar cell is provided having laminates formed by stacked lead frames to form an integral package supporting a solar cell structure. Lead frames serve as a heat sink, raised portions match a cavity in a middle lead frames that contain and hold individual solar cell chips in place. Beveled interior edges of a carrier lead frame are in electrical contact with bus bars on the periphery of a suspended solar cell and form the electrical connection for the cell, maximizing current handling capability and allowing the use of spring tension and/or a bonding compound for additional connection strength and integrity. Such a “stackable” semiconductor package requires no ribbon bonding and has multiple bias options, maximum scalability, enhanced moisture resistance, and multiple attachment options for heat sink attachment.

Abstract: A lattice-matched solar cell having a dilute nitride-based sub-cell has exponential doping to thereby control current-carrying capacity of the solar cell. Specifically a solar cell with at least one dilute nitride sub-cell that has a variably doped base or emitter is disclosed. In one embodiment, a lattice matched multi junction solar cell has an upper sub-cell, a middle sub-cell and a lower dilute nitride sub-cell, the lower dilute nitride sub-cell having doping in the base and/or the emitter that is at least partially exponentially doped so as to improve its solar cell performance characteristics. In construction, the dilute nitride sub-cell may have the lowest bandgap and be lattice matched to a substrate, the middle cell typically has a higher bandgap than the dilute nitride sub-cell while it is lattice matched to the dilute nitride sub-cell. The upper sub-cell typically has the highest bandgap and is lattice matched to the adjacent sub-cell.

Abstract: In a solar cell having one or more subcells, at least one subcell is provided with a reverse heterojunction, the reverse heterojunction being formed with an emitter and an adjacent base, wherein the emitter has a band gap that is at least 10 meV lower than that of the adjacent base in order to reduce sheet resistance of the emitter and/or increase the subcell current with minimal effect on the open-circuit voltage. Because of the increase in current, the decrease in emitter sheet resistance, and relatively unchanged open-circuit voltage of the subcell, the efficiency of a solar cell employing one or more subcells with reverse heterojunctions is enhanced.

Abstract: The present disclosure provides multi-junction solar cell structures and fabrication methods thereof that improve electrical testing capability and reduce chip failure rates. In the present invention a special masking pattern is used in the layout such that all or some of the epitaxial layers are etched away in the corner areas of each solar cell. Consequently, the semiconductor substrate or one or more of the interconnections between junctions become accessible from the top (the side facing the sun) to make electrical connections.

Abstract: An alloy composition for a subcell of a solar cell is provided that has a bandgap of at least 0.9 eV, namely, Ga1-xInxNyAs1-y-zSbz with a low antimony (Sb) content and with enhanced indium (In) content and enhanced nitrogen (N) content, achieving substantial lattice matching to GaAs and Ge substrates and providing both high short circuit currents and high open circuit voltages in GaInNAsSb subcells for multijunction solar cells. The composition ranges for Ga1-xInxNyAs1-y-zSbz are 0.07?x?0.18, 0.025?y?0.04 and 0.001?z?0.03.

Abstract: Photovoltaic cells with one or more subcells are provided with a wide band gap, pseudomorphic window layer of at least 15 nm in thickness and with an intrinsic material lattice constant that differs by at least 1% from an adjacent emitter layer. This window layer has a higher band gap than a window layer with substantially the same intrinsic material lattice constant as the adjacent emitter layer, which increases the light transmission through the window, thereby increasing the current generation in the solar cell. The quality of being pseudomorphic material preserves a good interface between the window and the emitter, reducing the minority carrier surface recombination velocity. A method is provided for building a wide band gap, pseudomorphic window layer of a photovoltaic cell that has an intrinsic material lattice constant that differs by at least 1% from the adjacent emitter layer.

Abstract: Multijunction solar cells having at least four subcells are disclosed, in which at least one of the subcells comprises a base layer formed of an alloy of one or more elements from group III on the periodic table, nitrogen, arsenic, and at least one element selected from the group consisting of Sb and Bi, and each of the subcells is substantially lattice matched. Methods of manufacturing solar cells and photovoltaic systems comprising at least one of the multijunction solar cells are also disclosed.

Abstract: A device containing a solar cell chip that may include a hermetically sealed chamber containing optical matching fluid and a threaded pedestal mounting to allow for replacement of solar cell units and that are easily mountable to a master heat sink.

Abstract: A device containing a solar cell is provided in the form of a stacked package that has a planar arrangement of conductive laminates at or below the surface of a heat sink. The planar alignment allows placement of electrical connections below the surface of the heat sink and reduces the vertical profile of the device, making it easier to be hermetically sealed. In specific embodiments the solar cell substrate is embedded within the heat sink during the manufacturing phase, eliminating the need for a thermally conductive substrate between the solar cell and the heat sink.

Abstract: A semiconductor light detection device fabrication technique is provided in which the cap etch and anti-reflection coating steps are performed in a single, self-aligned lithography module.

Abstract: An alloy composition for a subcell of a solar cell is provided that has a bandgap of at least 0.9 eV, namely, Ga1-xInxNyAs1-y-zSbz with a low antimony (Sb) content and with enhanced indium (In) content and enhanced nitrogen (N) content, achieving substantial lattice matching to GaAs and Ge substrates and providing both high short circuit currents and high open circuit voltages in GaInNAsSb subcells for multijunction solar cells. The composition ranges for Ga1-xInxNyAs1-y-zSbz are 0.07?x?0.18, 0.025?y?0.04 and 0.001?z?0.03.