Abstract: Solar cells, particularly GaAs/GaSb tandem solar cells, are mechanically and electrically connected in the form of a string using a flexible circuit tape and mounted in optical alignment with solar energy concentrators in a module. A heat spreader body is attached to each cell unit as part of a heat sink and the cells are precisely positioned to provide optical alignment. The flexible circuit tape is formed by conductive strips sandwiched between layers of polymer dielectric tape and provided with tabs at predefined holes in the tape for bonding to current carrying surfaces of concentrated sunlight tandem solar cell units.

Abstract: Solar cells, particularly GaAs/GaSb tandem solar cells, are mounted on a honeycomb light weight panel in optical alignment with solar energy concentrators mounted on a front panel side. The cells are mounted on metallized surfaces of the heat spreader that is attached to a panel wall rear panel side. A circuit carrier has conductors which are bonded to metallization islands that are on one side only of the heat spreader. The circuit carrier is adhered to the rear panel side.

Abstract: A photovoltaic cell array involving rows and columns of tandem or stacked solar cell units composed of GaSa/GaSb associated with a radiation collector have produced measured energy conversion efficiencies of 31% AMO. The booster GaSb cell is manufactured by a process which produces a p-type diffusion region within an n-type substrate, has improved energy conversion efficiencies and can be mounted as part of a four terminal stacked solar cell unit.

Abstract: A thermal cracking apparatus for cracking organic or inorganic gases is described. More particularly, the thermal cracker cracks inorganic gases such as arsine and phosphine for use in the growth of III-V compound semiconductor layers. The design of the apparatus minimizes the uptake of contaminants into the cracked gas stream.

Abstract: A vacuum chemical epitaxy apparatus comprising a first mixing chamber having an inlet for introducing a metal-organic gaseous materials and n-type and p-type dopants, and a plurality of outlets for directing the flow of said metal-organic gases and n-type and p-type dopants toward a substrate; a second mixing chamber disposed below said first chamber having an inlet for introducing a metal-organic gaseous material and n-type and p-type dopants, and a plurality of passages through said first chamber and an outlet for each passage, wherein the passage outlets are in substantially the same plane with the outlets of the first chamber; and means for exhausting the metal-organic gaseous materials and n-type and p-type dopants from the second chamber.

Abstract: An injection block having a plurality of geometrically arranged injection sources for gaseous Group III metal organic compounds is oriented substantially perpendicular to the placement of at least one semiconductor wafer substrate within a vacuum reaction chamber. The injector sources are sized to provide disbursing flow of the compounds capable of depositing a layer of about 5% uniform thickness or less over substantially the entire semiconductor wafer. An injection source of Group V compounds is located centrally within the geometrically arranged injection sources for the Group III compounds. The Group V injection source is sized to supply an excess of the Group V compounds required to react with the Group III compounds in order to form Group III-V semiconductor layers on the substrate and partition the Group III sources into groups having substantially equal numbers of injection sources. An excess of Group V comounds is injected.

Abstract: The present invention is an apparatus of mechanically stacked photovoltaic cells having two cells. The bottom cell has a layer of GaSb having regions of different conductivity forming a homojunction therein. The GaSb layer is sandwiched between a conductive substrate and a bottom passivating layer. In the bottom cell is a means for forming electrical contacts to the substrate and the incident surface of the bottom passivating layer. The top cell has a layer of GaAs having regions of different conductivity forming a homojunction therein, a top passivating layer contacting the surface of the layer of GaAs which is incident to solar radiation, and a means for forming electrical contacts to the layer of GaAs opposed to solar radiation and the incident surface of the passivating layer.

Abstract: A heater apparatus particularly suitable for use in a vacuum deposition apparatus is disclosed. The heater apparatus contains an open structure surrounding the heating element to permit quick evacuation of the apparatus and avoid memory problems attendant with sealed heater tubes used in a high vacuum environment which is repeatedly cycled from vacuum to ambient pressure.

Abstract: The present invention is an apparatus of mechanically stacked photovoltaic cells having a bottom heat spreader and a top heat spreader, a bottom photovoltaic cell and a top photovoltaic cell, and means for forming the necessary electrical contacts. The heat spreaders are electrically insulated from each other but are thermally connected to each other. The bottom photovoltaic cell has an anode and a cathode and is thermally bonded to the bottom heat spreader and is thermally connected to the top heat spreader. The top photovoltaic cell has an anode and a cathode, is electrically insulated from the bottom photovoltaic cell, and is thermally bonded to the top heat spreader and is thermally connected to the bottom heat spreader.

Abstract: A photovolatic device is disclosed comprising a p-type conductive substrate, a sandwich of p-type Al.sub.y Ga.sub.(1-y) As bottom layer/p-type GaAs base layer/p-type Al.sub.y Ga.sub.(1-y) As top layer (wherein the surface area of the p-type Al.sub.y Ga.sub.(1-y) As top layer is less than the surface area of the p-type GaAs base layer, a layer of n.sup.+ -type GaAs emitter contacting the surface of the p-type GaAs base layer (wherein the surface area of the layer of n.sup.+ -type GaAs emitter is less than one-tenth the surface area of the p-type GaAs base layer), an insulating layer contacting the surface of the p-type Al.sub.y Ga.sub.(1-y) As top layer, and means for forming electrical contacts to the substrate and the incident surface of the n.sup.+ -type GaAsemitter layer.

Abstract: A mechanically stacked module package is described. The package permits the effective mechanical stacking of two solar cells in a compact arrangement. The design also permits the easy wiring of the package into a voltage matching configuration for module wiring thus eliminating the problems of current matching the top and bottom cells. The package design can be used with any mechanically stacked cells although the design is most suitable for concentrator solar cell configurations where the removal of heat to avoid degradation and shortening of lifetime is a major concern.

Abstract: Two- and three-terminal ternary III-V two-color and three-color solar cells which incorporate GaAs.sub.1-x-y P.sub.x Sb.sub.y transparent window layers are described. The window layers lower the surface recombination of the incident homojunction layer.

Abstract: Three-terminal ternary III-V two-color solar cells incorporating layers of GaAs.sub.1-x-y P.sub.x Sb.sub.y. The three-terminal structure enables the current to be withdrawn from both cells without the necessity of current matching between the two color stacked photovoltaic device. In addition, the three-terminal configuration permits the independent determination of the individual properties of each cell. The stacked two-color cells can be connected in series through the three-terminal arrangement to overcome the problems of independent load matching between the cells encountered with the conventional two-terminal configuration. Finally, the three-terminal two colored solar cells does not require a shorting junction between the homojunction layers of the cells but only a simple transition layer. This speeds the processing of the device.

Abstract: Ternary III-V multicolor solar cells incorporating layers of GaAs.sub.1-x-y P.sub.x Sb.sub.y and an improved process of fabricating multicolor photovoltaic III-V compound photovoltaic devices.

Abstract: A new high efficiency, multijunction photovoltaic solar cell for use with a concentrating lens. This cell comprises an elemental single crystal substrate without an internal light sensitive junction, upon which are two or more successive homogenous layers of semiconductor material, each layer containing within it a light sensitive p/n junction of a similar polarity, each layer having essentially the same lattice constant as the single crystal substrate, each layer having a shorting junction contact with the layer immediately above and below it, each successive layer adsorbing light energy at a shorter wavelength, and each layer being of sufficient thickness and appropriate composition to develop essentially the same current as the other layers. The outer surfaces of the top layer and the substrate are provided with electrical contacts for distribution of the electric current.

Abstract: A new high efficiency, multijunction photovoltaic solar cell for use with a concentration lens. This cell comprises an elemental single crystal substrate without an internal light sensitive junction, upon which are two or more successive homogenous layers of semiconductor materials, each layer containing within it a light sensitive p/n junction of a similar polarity, each layer having essentially the same lattice constant as the single crystal substrate, each layer having a shorting junction contact with the layer immediately above and below it, each successive layer adsorbing light energy at a shorter wavelength, and each layer being of sufficient thickness and appropriate composition to develop essentially the same current as the other layers. At the junction, between the successive layers of the multilayer cell, a thin pseudo transparent low bandgap semiconductor layer is provided at the shorting junction interface.

Abstract: The specification describes a gallium aluminum arsenide-gallium arsenide-germanium solar cell and fabrication process therefor wherein the deposition of a layer of gallium aluminum arsenide establishes a first PN junction in the GaAs of one bandgap energy on one side of a gallium arsenide substrate, and the deposition of a layer of germanium establishes a second PN junction in Ge of a different bandgap energy on the other side of the GaAs substrate. The two PN junctions are responsive respectively to different wavelength ranges of solar energy to thus enhance the power output capability of a single wafer (substrate) solar cell. Utilization of the Group IV element germanium, as contrasted to compound semiconductors, simplifies the process control requirements relative to known prior art compound semiconductor processes, and germanium also provides a good crystal lattice match with gallium arsenide and thereby maximizes process yields.

Abstract: An apparatus and method for epitaxial film formation is disclosed. Planar reactive evaporation techniques suitable for scaling are employed to produce high purity compound semiconducting films at relatively low temperatures.

Abstract: The specification describes a gallium aluminum arsenide-gallium arsenide-germanium solar cell and fabrication process therefor wherein the deposition of a layer of gallium aluminum arsenide establishes a first PN junction in the GaAs of one bandgap energy on one side of a gallium arsenide substrate, and the deposition of a layer of germanium establishes a second PN junction in Ge of a different bandgap energy on the other side of the GaAs substrate. The two PN junctions are responsive respectively to different wavelength ranges of solar energy to thus enhance the power output capability of a single wafer (substrate) solar cell. Utilization of the Group IV element germanium, as contrasted to compound semiconductors, simplifies the process control requirements relative to known prior art compound semiconductor processes, and germanium also provides a good crystal lattice match with gallium arsenide and thereby maximizes process yields.

Abstract: The specification describes a compound semiconductor solar cell and fabrication process therefor wherein both the P and N-type layers of the cell are polycrystalline semiconducting material and have large crystallites with grain boundaries of similar dimensions and spacings. These grain boundaries are spaced apart by a distance substantially greater than the optical absorption length, .LAMBDA., in one of the layers and by an amount sufficient to permit substantial numbers of photon-generated carriers in that one layer to cross the PN junction between the layers. Thus, substantial power is generated without the requirement for using expensive monocrystalline semiconductive materials.