Abstract: A photovoltaic cell or other optoelectronic device having a wide-bandgap semiconductor used in the window layer. This wider bandgap is achieved by using a semiconductor composition that is not lattice-matched to the cell layer directly beneath it and/or to the growth substrate. The wider bandgap of the window layer increases the transmission of short wavelength light into the emitter and base layers of the photovoltaic cell. This in turn increases the current generation in the photovoltaic cell. Additionally, the wider bandgap of the lattice mismatched window layer inhibits minority carrier injection and recombination in the window layer.

Abstract: A perfectly or approximately lattice-matched semiconductor layer for use in an electronic or optoelectronic device. Perfectly lattice-matched (“PLM”) semiconductor layers prevent or lessen the formation and propagation of crystal defects in semiconductor devices, defects that can decrease the performance characteristics of the device. For some semiconductors, the ability to optimize composition-dependent properties over the wider range of compositions that approximately lattice-matched (“ALM”) semiconductor layers allows is more advantageous than the lower strain and dislocation density encountered for PLM layers. In addition, PLM cell layers and ALM cell layers are also expected to result in improved radiation resistance characteristics for some semiconductor devices.

Abstract: A photovoltaic cell or other optoelectronic device having a wide-bandgap semiconductor used in the window layer. This wider bandgap is achieved by using a semiconductor composition that is not lattice-matched to the cell layer directly beneath it and/or to the growth substrate. The wider bandgap of the window layer increases the transmission of short wavelength light into the emitter and base layers of the photovoltaic cell. This in turn increases the current generation in the photovoltaic cell. Additionally, the wider bandgap of the lattice mismatched window layer inhibits minority carrier injection and recombination in the window layer.

Abstract: A perfectly or approximately lattice-matched semiconductor layer for use in an electronic or optoelectronic device. Perfectly lattice-matched (“PLM”) semiconductor layers prevent or lessen the formation and propagation of crystal defects in semiconductor devices, defects that can decrease the performance characteristics of the device. For some semiconductors, the ability to optimize composition-dependent properties over the wider range of compositions that approximately lattice-matched (“ALM”) semiconductor layers allows is more advantageous than the lower strain and dislocation density encountered for PLM layers. In addition, PLM cell layers and ALM cell layers are also expected to result in improved radiation resistance characteristics for some semiconductor devices.

Abstract: A multilayer semiconductor structure includes a germanium substrate having a first surface. The germanium substrate has two regions, a bulk p-type germanium region, and a phosphorus-doped n-type germanium region adjacent to the first surface. A layer of a phosphide material overlies and contacts the first surface of the germanium substrate. A layer of gallium arsenide overlies and contacts the layer of the phosphide material, and electrical contacts may be added to form a solar cell. Additional photovoltaic junctions may be added to form multijunction solar cells. The solar cells may be assembled together to form solar panels.

Abstract: An improved photovoltaic cell, according to one embodiment, includes a base layer; a primary window layer having a first type of doping, with the primary window layer being disposed over the base layer; and a secondary window layer having the first type of doping, with the secondary window layer being disposed over the primary window layer. In another embodiment, the improved photovoltaic cell has a multilayer back-surface field structure; a base layer disposed over the back-surface field structure; and a primary window layer disposed over the base layer. In yet another embodiment, the photovoltaic cell includes a base layer; and a primary window layer disposed over the base layer, with the primary window layer having a thickness of at least about 1000 Angstroms.

Abstract: An improved photovoltaic cell, according to one embodiment, includes a base layer; a primary window layer having a first type of doping, with the primary window layer being disposed over the base layer; and a secondary window layer having the first type of doping, with the secondary window layer being disposed over the primary window layer. In another embodiment, the improved photovoltaic cell has a multilayer back-surface field structure; a base layer disposed over the back-surface field structure; and a primary window layer disposed over the base layer. In yet another embodiment, the photovoltaic cell includes a base layer; and a primary window layer disposed over the base layer, with the primary window layer having a thickness of at least about 1000 Angstroms.

Abstract: A method of making group I-III-VI compound semiconductors such as copper indium diselenide for use in thin film heterojunction photovoltaic devices. A composite film of copper, indium, and possibly other group IIIA elements, is deposited upon a substrate. A separate film of selenium is deposited on the composite film. The substrate is then heated in a chamber in the presence of a gas containing hydrogen to form the compound semiconductor material.

Abstract: 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.

Abstract: A method for fabricating a copper indium diselenide semiconductor film comprising use of DC magnetron sputtering apparatus to sequentially deposit a first film of copper on a substrate and a second film of indium on the copper film. Thereafter the substrate with copper and indium films is heated in the presence of gas containing selenium at a temperature selected to cause interdiffusion of the elements and formation of a high quality copper indium diselenide film. In a preferred form, an insulating substrate is used and an electrical contact is first deposited thereon in the same DC magnetron sputtering apparatus prior to deposition of the copper and indium films.

Abstract: A thin film photovoltaic device having first layer of copper indium selenide, a second layer of cadmium sulfide having a thickness less than 2500 angstroms, and a third layer of conducting wide bandgap semiconductor such as zinc oxide. The transparent third layer allows good transmission of blue light to the junction region while fully depleting the junction area to improve device voltage.