Abstract: Apparatus and Method for Optimizing the Efficiency of a Bypass Diode in Solar Cells. In a preferred embodiment, a layer of TiAu is placed in an etch in a solar cell with a contact at a doped layer of GaAs. Electric current is conducted through a diode and away from the main cell by passing through the contact point at the GaAs and traversing a lateral conduction layer. These means of activating, or “turning on” the diode, and passing the current through the circuit results in greater efficiencies than in prior art devices. The diode is created during the manufacture of the other layers of the cell and does not require additional manufacturing.

Abstract: A multijunction solar cell including an upper first solar subcell, and the base-emitter junction of the upper first solar subcell being a homojunction; a second solar subcell adjacent to said first solar subcell; a third solar subcell adjacent to said second solar subcell. A first graded interlayer is provided adjacent to said third solar subcell. A fourth solar subcell is provided adjacent to said first graded interlayer, said fourth subcell is lattice mismatched with respect to said third subcell. A second graded interlayer is provided adjacent to said fourth solar subcell; and a lower fifth solar subcell is provided adjacent to said second graded interlayer, said lower fifth subcell is lattice mismatched with respect to said fourth subcell.

Abstract: A solar cell includes a semiconductor substrate and a sequence of semiconductor layers disposed over the substrate. The sequence of semiconductor layers includes a semiconductor window layer. The solar cell also includes a semiconductor silicon-containing cap layer over the window layer. The cap layer is spatially separated from the window layer by a semiconductor barrier layer that either includes no silicon or has a silicon concentration that is significantly lower than the silicon concentration of the cap layer.

Abstract: An integral semiconductor device having a sequence of layers of semiconductor material. The semiconductor device may include a first region in which the sequence of layers of semiconductor material forms at least one cell of a multijunction solar cell including a metamorphic layer with a graded lattice constant. The semiconductor device may also include a second region, spaced apart from the first region, in which the sequence of layers in the second region forms a support for a bypass diode that functions to pass current when the solar cell is shaded.

Abstract: A multijunction solar cell is fabricated according to an embodiment by providing a substrate, depositing a nucleation first layer over and directly in contact with the substrate, depositing a second layer containing an arsenic dopant over the nucleation layer and depositing a sequence of layers over the second layer forming at least one solar subcell. The nucleation layer serves as a diffusion barrier to the arsenic dopant such that diffusion of the arsenic dopant into the substrate is limited in depth by the nucleation layer.

Abstract: In a preferred embodiment, a layer of TiAu is placed in an etch in a solar cell with a contact at a doped layer of GaAs. Electric current is conducted through a diode and away from the main cell by passing through the contact point at the GaAs and traversing a lateral conduction layer. These means of activating, or “turning on” the diode, and passing the current through the circuit results in greater efficiencies than in prior art devices. The diode is created during the manufacture of the other layers of the cell and does not require additional manufacturing.

Abstract: A method of manufacturing a solar cell by providing a gallium arsenide carrier with a prepared bonding surface; providing a sapphire substrate; bonding the gallium arsenide carrier and the sapphire substrate to produce a composite structure; detaching the bulk of the gallium arsenide carrier from the composite structure, leaving a gallium arsenide growth substrate on the sapphire substrate; and depositing a sequence of layers of semiconductor material forming a solar cell on the growth substrate. For some solar cells, the method further includes mounting a surrogate second substrate on top of the sequence of layers of semiconductor material forming a solar cell; and removing the growth substrate.

Abstract: A multijunction solar cell including first and second solar cells on a substrate with an integral bypass diode having an intrinsic layer and operative for passing current when the multijunction solar cell is shaded. In one embodiment, a vertical sequence of solar cells are epitaxially grown on a first portion of the substrate, and the layers of the diode are epitaxially grown on a second portion of the substrate with the layers of the bypass diode being deposited subsequent to the layers of the top solar cell.

Abstract: A solar cell including a semiconductor body with a multijunction solar cell and an integral bypass diode, at least one via extending between the upper and lower surfaces of the semiconductor body and electrically conducting elements of the solar cell.

Abstract: A method of manufacturing a solar cell by providing a gallium arsenide carrier with a prepared bonding surface; providing a sapphire substrate; bonding the gallium arsenide carrier and the sapphire substrate to produce a composite structure; detaching the bulk of the gallium arsenide carrier from the composite structure, leaving a gallium arsenide growth substrate on the sapphire substrate; and depositing a sequence of layers of semiconductor material forming a solar cell on the growth substrate. For some solar cells, the method further includes mounting a surrogate second substrate on top of the sequence of layers of semiconductor material forming a solar cell; and removing the growth substrate.

Abstract: A solar cell array including a first solar cell with an integral bypass diode and an adjacent second solar cell and two discrete metal interconnection members coupling the anode of the bypass diode of the first cell with the anode of the second solar cell.

Abstract: A method of manufacturing a mounted solar cell by providing a metallic flexible film having a predetermined coefficient of thermal expansion; and attaching the semiconductor solar cell to the metallic film, the coefficient of thermal expansion of the semiconductor body closely matching the predetermined coefficient of thermal expansion of the metallic film.

Abstract: A solar cell including a semiconductor body with a multijunction solar cell and an integral bypass diode, and a pair of vias extending between the upper and lower surfaces, forming determined on the lower surface and electrically coupling the anode of the bypass diode with the conductive grid on the upper surface.

Abstract: A system for generating electrical power from solar radiation utilizing a III-V compound multijunction semiconductor solar cell; a concentrator for focusing sunlight on the solar cell; and a heat spreader connected to the solar cell for cooling the cell. The solar cell is preferably an inverted metamorphic multijunction solar cell.

Abstract: Dopant diffusion into semiconductor material is controlled during fabrication of a semiconductor structure by depositing a nucleation layer over a first layer of the semiconductor structure and depositing a device layer containing the dopant over the nucleation layer. The nucleation layer serves as a diffusion barrier by limiting in depth the diffusion of the dopant into the first layer. The dopant can include arsenic (As).

Abstract: A method of making a multijunction solar cell, including first and second solar cells on a substrate with a bypass diode having an intrinsic layer and operative for passing current when the multijunction solar cell is shaded. In one embodiment, a vertical sequence of solar cells are epitaxially grown on a first portion of the substrate, and the layers of the diode are epitaxially grown on a second portion of the substrate with the layers of the bypass diode being deposited subsequent to the layers of the top solar cell.

Abstract: A double-sided photovoltaic package with an incident photovoltaic cell and a reflective photovoltaic cell. Both photovoltaic cells have a corresponding absorbing surface for absorbing solar radiation. The incident photovoltaic cell and the reflective photovoltaic cell are arranged so that when the absorbing surface of the incident photovoltaic cell is located to receive incident non-reflected solar radiation the absorbing surface of the reflective photovoltaic cell is located to receive reflected solar radiation. The structure of the incident photovoltaic cell is adapted to convert non-reflected light to electrical energy and the structure of the reflective photovoltaic cell is adapted to convert reflected light to electrical energy. Additionally, in the preferred embodiment, the incident photovoltaic cell and the reflective photovoltaic cell both comprise inverted metamorphic multijunction photovoltaic cells.

Abstract: A system for generating electrical power from solar radiation utilizing a thin film III-V compound multijunction semiconductor solar cell mounted on a support in a non-planar configuration.

Abstract: A method of forming a multijunction solar cell comprising an upper subcell, a middle subcell, and a lower subcell by providing a first substrate for the epitaxial growth of semiconductor material; forming a first solar subcell on said substrate having a first band gap; forming a second solar subcell over said first subcell having a second band gap smaller than said first band gap; forming a grading interlayer over said second subcell having a third band gap larger than said second band gap; forming a third solar subcell having a fourth band gap smaller than said second band gap such that said third subcell is lattice mismatched with respect to said second subcell; and etching a via from the top of the third subcell to the substrate to enable both anode and cathode contacts to be placed on the backside of the solar cell.

Abstract: Apparatus and Method for Optimizing the Efficiency of Germanium Junctions in Multi-Junction Solar Cells. In a preferred embodiment, an indium gallium phosphide (InGaP) nucleation layer is disposed between the germanium (Ge) substrate and the overlying dual-junction epilayers for controlling the diffusion depth of the n-doping in the germanium junction. Specifically, by acting as a diffusion barrier to arsenic (As) contained in the overlying epilayers and as a source of n-type dopant for forming the germanium junction, the nucleation layer enables the growth time and temperature in the epilayer device process to be minimized without compromising the integrity of the dual-junction epilayer structure. This in turn allows the arsenic diffusion into the germanium substrate to be optimally controlled by varying the thickness of the nucleation layer.