Embodiments described herein relate to a dual-band photodetector. The dual-band photodetector includes a barrier layer (10) disposed between two infrared absorption layers (8, 12) wherein the barrier layer (10) is lattice matched to at least one of the infrared absorption layers (8, 12). Furthermore, one infrared absorption layer includes dilute nitride to adjust the band gap to a desired cut-off wavelength while maintaining valence-band alignment with the barrier layer. Embodiments also relate to a system and processes for producing the photodetector fabricated from semiconductor materials.

A method of forming a layered OP material is provided, where the layered OP material comprises an OPGaAs template, and a layer of GaP on the OPGaAs template. The OPGaAs template comprises a patterned layer of GaAs having alternating features of inverted crystallographic polarity of GaAs. The patterned layer of GaAs comprises a first feature comprising a first crystallographic polarity form of GaAs having a first dimension, and a second feature comprising a second crystallographic polarity form of GaAs having a second dimension. The layer of GaP on the patterned layer of GaAs comprises alternating regions of inverted crystallographic polarity that generally correspond to their underlying first and second features of the patterned layer of GaAs. Additionally, each of the alternating regions of inverted crystallographic polarity of GaP are present at about 100 micron thickness or more.

A multijunction solar cell including an upper first solar subcell having a first band gap; a second solar subcell adjacent to the first solar subcell and having a second band gap smaller than the first band gap; a first graded interlayer adjacent to the second solar subcell; the first graded interlayer having a third band gap greater than the second band gap; and a third solar subcell adjacent to the first graded interlayer, the third subcell having a fourth band gap smaller than the second band gap such that the third subcell is lattice mismatched with respect to the second subcell. A second graded interlayer is provided adjacent to the third solar subcell; the second graded interlayer having a fifth band gap greater than the fourth band gap; and a lower fourth solar subcell is provided adjacent to the second graded interlayer, the lower fourth subcell having a sixth band gap smaller than the fourth band gap such that the fourth subcell is lattice mismatched with respect to the third subcell.

Embodiments of the invention generally relate to device fabrication of thin films used as solar devices or other electronic devices, and include textured back reflectors utilized in solar applications. In one embodiment, a method for forming a textured metallic back reflector which includes depositing a metallic layer on a gallium arsenide material within a thin film stack, forming an array of metallic islands from the metallic layer during an annealing process, removing or etching material from the gallium arsenide material to form apertures between the metallic islands, and depositing a metallic reflector layer to fill the apertures and cover the metallic islands. In another embodiment, a textured metallic back reflector includes an array of metallic islands disposed on a gallium arsenide material, a plurality of apertures disposed between the metallic islands and extending into the gallium arsenide material, a metallic reflector layer disposed over the metallic islands, and a plurality of reflector protrusions formed between the metallic islands and extending from the metallic reflector layer and into the apertures formed in the gallium arsenide material.

A method of forming a multijunction solar cell comprising at least an upper subcell, a middle subcell, and a lower subcell, the method including forming a first alpha layer over said middle solar subcell using a surfactant and dopant including selenium, the first alpha layer configured to prevent threading dislocations from propagating; forming a metamorphic grading interlayer over and directly adjacent to said first alpha layer; forming a second alpha layer using a surfactant and dopant including selenium over and directly adjacent to said grading interlayer to prevent threading dislocations from propagating; and forming a lower solar subcell over said grading interlayer such that said lower solar subcell is lattice mismatched with respect to said middle solar subcell.

A Dual-wavelength hybrid (DWH) device includes an n-type ohmic contact layer, cathode and anode terminal electrodes, first and second injector terminal electrodes, p-type and n-type modulation doped QW structures, and first through sixth ion implant regions. The first injector terminal electrode is formed on the third ion implant region that contacts the p-type modulation doped QW structure and the second injector terminal electrode is formed on the fourth ion implant region that contacts the n-type modulation doped QW structure. The DWH device operates in at least one of a vertical cavity mode and a whispering gallery mode. In the vertical cavity mode, the DWH device converts an in-plane optical mode signal to a vertical optical mode signal, whereas in the whispering gallery mode the DWH device converts a vertical optical mode signal to an in-plane optical mode signal.

Materials and methods may be provided for short-wave infrared (SWIR) superlattice materials. The superlattice material includes a first sub-layer comprising InAs, and a second sub-layer adjacent to the first sub-layer including AlSb, AlAsSb, or InAlAsSb.

A structure includes a silicon substrate; silicon readout circuitry disposed on a first portion of a top surface of the substrate and a radiation detecting pixel disposed on a second portion of the top surface of the substrate. The pixel has a plurality of radiation detectors connected with the readout circuitry. The plurality of radiation detectors are composed of at least one visible wavelength radiation detector containing germanium and at least one infrared wavelength radiation detector containing a Group III-V semiconductor material. A method includes providing a silicon substrate; forming silicon readout circuitry on a first portion of a top surface of the substrate and forming a radiation detecting pixel, on a second portion of the top surface of the substrate, that has a plurality of radiation detectors formed to contain a visible wavelength detector composed of germanium and an infrared wavelength detector composed of a Group III-V semiconductor material.

A low noise infrared photodetector has an epitaxial heterostructure that includes a photodiode and a transistor. The photodiode includes a high sensitivity narrow bandgap photodetector layer of first conductivity type, and a collection well of second conductivity type in contact with the photodetector layer. The transistor includes the collection well, a transfer well of second conductivity type that is spaced from the collection well and the photodetector layer, and a region of first conductivity type between the collection and transfer wells. The collection well and the transfer well are of different depths, and are formed by a single diffusion.

A semiconductor device and the like having high quantum efficiency or high sensitivity in a near-infrared to infrared region is provided. The semiconductor device includes: a substrate; a multiple quantum well structure disposed on the substrate, and including a plurality of pairs of a layer a and a layer b; and a crystal-adjusting layer disposed between the substrate and the multiple quantum well structure. The crystal-adjusting layer includes a first adjusting layer which is made of the same material as the substrate and is in contact with the substrate, and a second adjusting layer which is made of the same material as the layer a or the layer b of the multiple quantum well structure and is in contact with the multiple quantum well structure.