An optoelectronic device including a substrate having a surface, openings which extend in the substrate from the surface, and semiconductor elements, each semiconductor element partially extending into one of the openings and partially outside said opening, the height of each opening being at least 25 nm and at most 5 m and the ratio of the height to the smallest diameter of each opening being at least 0.5 and at most 15.

A photovoltaic device having three dimensional (3D) charge separation and collection, where charge separation occurs in 3D depletion regions formed between a p-type doped group III-nitride material in the photovoltaic device and intrinsic structural imperfections extending through the material. The p-type group III-nitride alloy is compositionally graded to straddle the Fermi level pinning by the intrinsic structural imperfections in the material at different locations in the group III-nitride alloy. A field close to the surfaces of the intrinsic defects separates photoexcited electron-hole pairs and drives the separated electrons to accumulate at the surfaces of the intrinsic defects. The intrinsic defects function as n-type conductors and transport the accumulated electrons to the material surface for collection. The compositional grading also creates a potential that drives the accumulated separated electrons toward an n-type group III-nitride layer for collection. The p-type group III-nitride alloy may comprise an alloy of InGaN, InAlN or InGaAlN.

A photodetector including a substrate, a light absorption layer arranged over the substrate, the light absorption layer including a stack including a semiconductor layer that absorbs light of a wavelength having an electric field vector parallel to a normal direction of a substrate surface, a lower contact layer arranged on a first side of the light absorption layer, a lower electrode contacting with the lower contact layer, an upper contact layer arranged on a second side of the light absorption layer, and an upper electrode contacting with the upper contact layer. An uneven structure including polarization-selective shapes of projections or depressions on the second side of the upper contact layer is provided, the shapes of projections or depressions each having a size of a wavelength or less of incident light in the semiconductor layer and half the wavelength or greater and being periodically arranged in at least one direction.

An optoelectronic device configured for improved light extraction through a region of the device other than the substrate is described. A group III nitride semiconductor layer of a first polarity is located on the substrate and an active region can be located on the group III nitride semiconductor layer. A group III nitride semiconductor layer of a second polarity, different from the first polarity, can located adjacent to the active region. A first contact can directly contact the group III nitride semiconductor layer of the first polarity and a second contact can directly contact the group III nitride semiconductor layer of the second polarity. Each of the first and second contacts can include a plurality of openings extending entirely there through and the first and second contacts can form a photonic crystal structure. Some or all of the group III nitride semiconductor layers can be located in nanostructures.

A heterostructure for use in an electronic or optoelectronic device is provided. The heterostructure includes one or more semiconductor layers containing columnar nanostructures (e.g., nanowires). The nanowire semiconductor layer can include sub-layers of varying composition, at least one of which is an active layer that can include quantum wells and barriers. A heterostructure can include n-type and p-type semiconductor contact layers adjacent to the nanowire semiconductor layer containing the active layer.

An alloy composition for a subcell of a solar cell is provided that has a bandgap of at least 0.9 eV, namely, Ga.sub.1-xIn.sub.xN.sub.yAs.sub.1-y-zSb.sub.z with a low antimony (Sb) content and with enhanced indium (In) content and enhanced nitrogen (N) content, achieving substantial lattice matching to GaAs and Ge substrates and providing both high short circuit currents and high open circuit voltages in GaInNAsSb subcells for multijunction solar cells. The composition ranges for Ga.sub.1-xIn.sub.xN.sub.yAs.sub.1-y-zSb.sub.z are 0.07x0.18, 0.025y0.04 and 0.001z0.03.

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 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.

An optoelectronic device with a multi-layer contact is described. The optoelectronic device can include a n-type semiconductor layer having a surface. A mesa can be located over a first portion of the surface of the n-type semiconductor layer and have a mesa boundary. A n-type contact region can be located over a second portion of the surface of the n-type semiconductor contact layer entirely distinct from the first portion, and be at least partially defined by the mesa boundary. A first n-type metallic contact layer can be located over at least a portion of the n-type contact region in proximity of the mesa boundary, where the first n-type metallic contact layer forms an ohmic contact with the n-type semiconductor layer. A second n-type metallic contact layer can be located over a second portion of the n-type contact region, where the second n-type metallic contact layer is formed of a reflective metallic material.

A method for producing a plurality of semiconductor components (1) is provided, comprising the following steps: a) providing a semiconductor layer sequence (2) having a first semiconductor layer (21), a second semiconductor layer (22) and an active region (25), said active region being arranged between the first semiconductor layer and the second semiconductor layer for generating and/or receiving radiation; b) forming a first connection layer (31) on the side of the second connection layer facing away from the first semiconductor layer; c) forming a plurality of cut-outs (29) through the semiconductor layer sequence; d) forming a conducting layer (4) in the cut-outs for establishing an electrically conductive connection between the first semiconductor layer and the first connection layer; and e) separating into the plurality of semiconductor components, wherein a semiconductor body (20) having at least one of the plurality of cut-outs arises from the semiconductor layer sequence for each semiconductor component and the at least one cut-out is completely surrounded by the semiconductor body in a top view of the semiconductor body. Furthermore, a semiconductor component is provided.