The present disclosure provides methods of fabricating a multijunction solar cell panel in which one or more of the steps are performed using an automated process. In some embodiments, the automated process uses machine vision.

A multijunction solar cell assembly and its method of manufacture including interconnected first and second discrete semiconductor body subassemblies disposed adjacent and parallel to each other, each semiconductor body subassembly 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 subassemblies form at least a four junction solar cell by a series connection being formed between the bottom solar subcell in the first semiconductor body and the bottom solar subcell in the second semiconductor body.

A stack-like III-V semiconductor product comprising a substrate and a sacrificial layer region arranged on an upper side of the substrate and a semiconductor layer arranged on an upper side of the sacrificial layer region. The substrate, the sacrificial layer region and the semiconductor layer region each comprise at least one chemical element from the main groups HI and a chemical element from the main group V. The sacrificial layer region differs from the substrate and from the semiconductor layer in at least one element. An etching rate of the sacrificial layer region differs from an etching rate of the substrate and from an etching rate of the semiconductor layer region at least by a factor of ten. The sacrificial layer region is adapted in respect of its lattice to the substrate and to the semiconductor layer region.

Solar cell structures comprising a plurality of solar cells, wherein each solar cell is separated from adjacent solar cell via a tunnel junction and/or a resonant tunneling structure (RTS), are described. Solar cells are implemented on Ge, Si, GaN, sapphire, and glass substrates. Each of the plurality of solar cells is at least partially constructed from a cell material which harnesses photons having energies in a predetermined energy range. In one embodiment each solar cell comprises of at least two sub-cells. It also describes a nano-patterned region/layer to implement high efficiency tandem/multi-junction solar cells that reduces dislocation density due to mismatch in lattice constants in the case of single crystalline and/or polycrystalline solar cells. Finally, solar structure could be used as light-emitting diodes when biased in forward biasing mode. The mode of operation could be determined by a programmed microprocessor.

A growth structure having a lattice transition (or graded buffer) or an engineered growth structure with a desired lattice constant, different from a lattice constant of conventional substrates like GaAs, Si, Ge, InP, under a release layer or an etch stop layer is used as a seed crystal for growing optoelectronic devices. The optoelectronic device can be a photovoltaic device having one or more subcells (e.g., lattice-matched or lattice-mismatched subcells). The release layer can be removed using different processes to separate the optoelectronic device from the growth structure, which may be reused, or from the engineered growth structure. When using the etch stop layer, the growth structure or the engineered growth structure may be grinded or etched away. The engineered growth structure may be made from a layer transfer process between two wafers or from a ternary and/or a quaternary material. Methods for making the optoelectronic device are also described.

In one aspect, semiconductor structures are described herein. A semiconductor structure, in some implementations, comprises a first semiconductor layer having a first bandgap and a first lattice constant and a second semiconductor layer having a second bandgap and a second lattice constant. The second lattice constant is lower than the first lattice constant. Additionally, a transparent metamorphic buffer layer is disposed between the first semiconductor layer and the second semiconductor layer. The buffer layer has a constant or substantially constant bandgap and a varying lattice constant. The varying lattice constant is matched to the first lattice constant adjacent the first semiconductor layer and matched to the second lattice constant adjacent the second semiconductor layer. The buffer layer comprises a first portion comprising Al.sub.yGa.sub.zIn.sub.(1-y-z)As and a second portion comprising Ga.sub.xIn.sub.(1-x)P. The first portion is adjacent the first semiconductor layer and the second portion is adjacent the second semiconductor layer.

A multi-junction solar cell having a first subcell made of an InGaAs compound. The first subcell has a first lattice constant and A second subcell has a second lattice constant. The first lattice constant is at least 0.008 greater than the second lattice constant. A metamorphic buffer is formed between the first subcell and the second subcell and has a sequence of at least three layers and a lattice constant increases from layer to layer in the sequence in the direction toward the first subcell. The lattice constants of the layers of the buffer are greater than the second lattice constant, and a layer of the metamorphic buffer has a third lattice constant that is greater than the first lattice constant. A number N of compensation layers for compensating the residual stress of the metamorphic buffer is formed between the metamorphic buffer and the first subcell.

A solar cell comprising an epitaxial sequence of layers of semiconductor material forming a solar cell deposited using an MOCVD reactor; a metal layer disposed on top of the sequence of layers of semiconductor material, the metal layer including a top surface layer composed of gold or silver; a polymer film; depositing a first metallic adhesion layer disposed on the polymer film that has a coefficient of thermal expansion substantially different from that of the top surface layer on one surface of the polymer film; a second metallic adhesion layer deposited over the first metallic adhesion layer and having a different composition from the first metallic adhesion layer and having no chemical elements in common; and the second metallic adhesion layer of the polymer film being permanently bonded to the metal layer of the sequence of layers of semiconductor material by a thermocompressive diffusion bonding technique.

The present disclosure provides a method of manufacturing a solar cell that includes providing a semiconductor growth substrate; depositing on said growth substrate a sequence of layers of semiconductor material forming a solar cell; applying a metal contact layer over said sequence of layers; affixing the adhesive polyimide surface of a permanent supporting substrate directly over said metal contact layer and permanently bonding it thereto by a thermocompressive technique; and removing the semiconductor growth substrate.

A multijunction solar cell assembly and its method of manufacture including first and second discrete semiconductor body subassemblies, each semiconductor body subassembly including first, second and third lattice matched subcells; a graded interlayer adjacent to the third solar subcell and functioning as a lateral conduction layer; and a fourth solar subcell adjacent to said graded interlayer being lattice mismatched with respect to the third solar subcell; wherein the average band gap of all four cells is greater than 1.44 eV.