An apparatus and method pertaining to a perpetual energy harvester. The harvester absorbs ambient infrared radiation and provides continual power regardless of the environment. The device seeks to harvest the largely overlooked blackbody radiation through use of a semiconductor thermal harvester.

A photovoltaic device, particularly a solar cell, comprises an interface between a layer of Group III-V material and a layer of Group IV material with a thin silicon diffusion barrier provided at or near the interface. The silicon barrier controls the diffusion of Group V atoms into the Group IV material, which is doped n-type thereby. The n-type doped region can provide the p-n junction of a solar cell in the Group IV material with superior solar cell properties. It can also provide a tunnel diode in contact with a p-type region of the III-V material, which tunnel diode is also useful in solar cells.

An integrated thin-film lateral multi-junction solar device and fabrication method are provided. The device includes, for instance, a substrate, and a plurality of stacks extending vertically from the substrate. Each stack may include layers, and be electrically isolated against another stack. Each stack may also include an energy storage device above the substrate, a solar cell above the energy storage device, a transparent medium above the solar cell, and a micro-optic layer of spectrally dispersive and concentrating optical devices above the transparent medium. Furthermore, the device may include a first power converter connected between the energy storage device and a power bus, and a second power converter connected between the solar cell and the power bus. Further, different solar cells of different stacks may have different absorption characteristics.

A photovoltaic cell is provided that can be used under high levels of solar concentration (1000 suns). The present cell includes at least one junction produced on a substrate based on gallium antimonide, the at least one junction having two alloys based on an antimonide material (Ga.sub.1-xAl.sub.xAs.sub.ySb.sub.1-y) lattice-matched on the substrate GaSb. If there are several junctions, two neighbouring junctions are separated by a tunnel junction.

A multijunction solar cell and its method of manufacture including interconnected first and second discrete semiconductor regions disposed adjacent and parallel to each other in a single semiconductor body, including first top subcell, second (and possibly third) lattice matched middle subcells; a graded interlayer adjacent to the last middle solar subcell; and a bottom solar subcell adjacent to said graded interlayer being lattice mismatched with respect to the last middle solar subcell; wherein the interconnected regions form at least a four junction solar cell by a series connection being formed between the bottom solar subcell in the first semiconductor region and the bottom solar subcell in the second semiconductor region.

A multijunction solar cell assembly and its method of manufacture including first and second discrete and different semiconductor body subassemblies which are electrically interconnected to form a five junction solar cell, each semiconductor body subassembly including first, second, third and fourth lattice matched subcells; wherein the average band gap of all four cells in each subassembly is greater than 1.44 eV.

Multijunction photovoltaic cells having at least three subcells are disclosed, in which at least one of the subcells comprises a base layer formed of GaInNAsSb. The GaInNAsSb subcells exhibit high internal quantum efficiencies over a broad range of irradiance energies.

A multijunction solar cell and its method of manufacture including interconnected first and second discrete semiconductor regions disposed adjacent and parallel to each other in a single semiconductor body, including first top subcell, second (and possibly third) lattice matched middle subcells; and a bottom solar subcell adjacent to said last middle subcell and lattice matched thereto; wherein the interconnected regions form at least a four junction solar cell by a series connection being formed between the bottom solar subcell in the first semiconductor region and the bottom solar subcell in the second semiconductor region.

Monolithic tandem chalcopyrite-perovskite photovoltaic devices and techniques for formation thereof are provided. In one aspect, a tandem photovoltaic device is provided. The tandem photovoltaic device includes a substrate; a bottom solar cell on the substrate, the bottom solar cell having a first absorber layer that includes a chalcopyrite material; and a top solar cell monolithically integrated with the bottom solar cell, the top solar cell having a second absorber layer that includes a perovskite material. A monolithic tandem photovoltaic device and method of formation thereof are also provided.

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.