In one aspect, optoelectronic devices are described herein. In some implementations, an optoelectronic device comprises a photovoltaic cell. The photovoltaic cell comprises a space-charge region, a quasi-neutral region, and a low bandgap absorber region (LBAR) layer or an improved transport (IT) layer at least partially positioned in the quasi-neutral region of the cell.

A multijunction solar cell including an upper first solar subcell having an emitter and base layers forming a photoelectric junction; a second solar subcell disposed under and adjacent to the upper first solar subcell, and having an emitter and base layers forming a photoelectric junction; and a third solar subcell disposed under and adjacent to the second solar subcell and having an emitter and base layers forming a photoelectric junction; wherein at least one of the base and emitter layers of at least a particular solar subcell from among the upper first solar subcell, the second solar subcell, and the third solar subcell has a graded band gap throughout at least a portion of thickness of its active layer adjacent to the photoelectric junction and being in a range of 20 to 300 MeV less than a band gap in the active layer in both the emitter layer and the base layer spaced away from the photoelectric junction.

An optical blocking region formed with patterned metal reduces light reflection toward pixel sensors in a pixel sensor array. The optical blocking region may be formed of a metal nanoscale grid in order to reflect more light away from the pixel sensors. The optical blocking region may include a dielectric layer, supporting the patterned metal, with high absorption structures or shallow deep trench isolation structures in order to increase absorption and thus reduce light reflection toward the pixel sensors.

A method of fabricating multijunction solar cell including an upper solar subcell and having an emitter of p conductivity type with a first band gap, and a base of n conductivity type with a second band gap greater than the first band gap; a lower solar subcell disposed below the upper solar subcell having an emitter of p conductivity type with a third band gap, and a base of n conductivity type with a fourth band gap greater than the third band gap; and an intermediate grading interlayer disposed between the upper and lower solar subcells and having a graded lattice constant that matches the upper first subcell on a first side and the second solar subcell on the second side opposite the first side, and having a fifth band gap that is greater than the second band gap of the upper solar subcell.

A method of fabricating multijunction solar cell including an upper solar subcell and having an emitter of p conductivity type with a first band gap, and a base of n conductivity type with a second band gap greater than the first band gap; a lower solar subcell disposed below the upper solar subcell having an emitter of p conductivity type with a third band gap, and a base of n conductivity type with a fourth band gap greater than the third band gap; and an intermediate grading interlayer disposed between the upper and lower solar subcells and having a graded lattice constant that matches the upper first subcell on a first side and the second solar subcell on the second side opposite the first side, and having a fifth band gap that is greater than the second band gap of the upper solar subcell.

A method of forming a semiconductor structure includes forming an opening in a dielectric layer, forming a recess in an exposed part of a substrate, and forming a lattice-mismatched crystalline semiconductor material in the recess and opening.

Embodiments of the invention generally relate to photovoltaic devices. In one embodiment, a method for forming a gallium arsenide based photovoltaic device includes providing a semiconductor structure, the structure including an absorber layer comprising gallium arsenide. A bypass function is provided in a p-n junction of the semiconductor structure, where under reverse-bias conditions the p-n junction breaks down in a controlled manner by a Zener breakdown effect.

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 monolithic multiple solar cell includes at least three partial cells, with a semiconductor mirror placed between two partial cells. The aim of the invention is to improve the radiation stability of said solar cell. For this purpose, the semiconductor mirror has a high degree of reflection in at least one part of a spectral absorption area of the partial cell which is arranged above the semiconductor mirror and a high degree of transmission within the spectral absorption range of the partial cell arranged below the semiconductor mirror.

Photovoltaic devices including direct gap III-V absorber materials and operatively associated back structures enhance efficiency by enabling photon recycling. The back structures of the photovoltaic devices include wide bandgap III-V layers, highly doped (In)GaAs layers, patterned oxide layers and metal reflectors that directly contact the highly doped (In)GaAs layers through vias formed in the back structures. Localized ohmic contacts are formed in the back structures of the devices.