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: In an electrical via structure and fabrication method that is particularly suited to coplanar contact solar cells, an initial opening (38,48a,48b,64) through the substrate is coated and substantially closed with a dielectric material (42,52,80). An inner opening (44) is then formed through the dielectric, and the via is provided with a conductive coating (46,54). The dielectric is initially applied in a liquid state and is thereafter cured to a solid. The need for strong chemical etchants to smooth the via opening prior to application of the dielectric and metallization is eliminated, and a polyimide dielectric on a GaAs/Ge solar cell has resulted in a substantial improvement in leakage resistance and cell efficiency.

Abstract: A photocell (40) includes a photovoltaic or otherwise photosensitive layer structure (44) on which a passivation or window layer (52) of an environmentally sensitive material such as aluminum gallium arsenide (AlGaAs) and an antireflection (AR) coating (54) are formed. An electrically conductive cap layer (60) delineated in a front contact grid configuration sealingly extends through the AR coating (54) to the window layer (52). An ohmic metal contact (64) is evaporated over and seals the cap layer (60) and the contiguous areas of the AR coating (54). The contact grid interface at which the cap layer (60) contacts the window layer (52) is sealed by the AR coating (54) and the contact (64). The photocell (40) is fabricated by forming, delineating and etching the cap layer (60), forming the AR coating (54) and then forming the contact (64) by evaporation of metal.

Abstract: A gallium arsenide solar cell is disclosed which employs a front aluminum gallium arsenide window layer. Metallic grid lines for charge carrier collection traverse the window layer and extend through this layer to the emitter layer. A flat conductive bar on the window layer crosses and makes electrical contact with the metallic grid lines. A flat metallic strip located on the window layer near an edge is spaced from the grid lines and conductive bar but is electrically coupled to the conductive bar by metallic bridges. Since the metallic strip is not in contact with the grid lines, external electrical connections can be affixed to the flat metallic strip using high temperature welding or soldering techniques without damage to the semiconductor body.