An optoelectronic device comprises a substrate; pads on a surface of the substrate; semiconductor elements, each element resting on a pad; a portion covering at least the lateral sides of each pad, the portion preventing the growth of the semiconductor elements on the lateral sides; and a dielectric region extending in the substrate from the surface and connecting, for each pair of pads, one of the pads in the pair to the other pad in the pair. A method of manufacturing an optoelectronic device is also disclosed.

A semiconductor device includes a substrate, a first insulation layer formed on the substrate in a first region, a photon absorption seed layer formed on the first insulation layer in the first region and on the substrate in a second region separate from the first region, and a photon absorption layer formed on the photon absorption seed layer in the first region. The photon absorption seed layer has a particular structure that may assist in reducing dislocation density in a region that includes a photon absorption layer.

Provided is a photodetector including a substrate, a first doped region on the substrate, a second doped region having a ring structure, wherein the second doped region is provided in the substrate, surrounds the first doped region and is horizontally spaced apart from a side of the first doped region, an optical absorption layer on the first doped region, a contact layer on the optical absorption layer, a first electrode on the contact layer, and a second electrode on the second doped region.

Methods and systems for reducing dark current in a photodiode include heating a photodiode above room temperature. A reverse bias voltage is applied to the heated photodiode to reduce a dark current generated by the photodiode.

Thin freestanding nitride veneers can be used for the fabrication of semiconductor devices. These veneers are typically less than 100 microns thick. The use of thin veneers also eliminates the need for subsequent wafer thinning for improved thermal performance and 3D packaging.

A germanium single-crystal wafer comprises silicon with an atomic concentration of from 3×10.sup.14 atoms/cc to 10×10.sup.13 atoms/cc, boron with an atomic concentration of from 1×10.sup.16 atoms/cc to 10×10.sup.18 atoms/cc, and gallium with an atomic concentration of from 1×10.sup.16 atoms/cc to 10×10.sup.19 atoms/cc. Further provided are a method for preparing the germanium single-crystal wafer, a method for preparing a germanium single-crystal ingot, and the use of the germanium single-crystal wafer for increasing the open-circuit voltage of a solar cell. The germanium single-crystal wafer has an improved electrical property in that it has a smaller difference in resistivity and carrier concentration.

A method of manufacturing a multijunction solar cell having an upper first solar subcell composed of a semiconductor material having a first band gap; a second solar subcell adjacent to said first solar subcell and composed of a semiconductor material having a second band gap smaller than the first band gap and being lattice matched with the upper first solar subcell; a third solar subcell adjacent to said second solar subcell and composed of a semiconductor material having a third band gap smaller than the second band gap and being lattice matched with the second solar subcell; a graded interlayer adjacent to the third solar subcell; and a fourth solar subcell adjacent to said graded interlayer and composed of a semiconductor material having a fourth band gap smaller than the third band gap and being lattice mismatched with respect to the third solar subcell; wherein the fourth subcell has a direct bandgap of greater than 0.75 eV.

Structures for a photodetector and methods of fabricating a structure for a photodetector. A photodetector may have a light-absorbing layer comprised of germanium. A waveguide core may be coupled to the light-absorbing layer. The waveguide core may be comprised of a dielectric material, such as silicon nitride. Another waveguide core, which may be comprised of a different material such as single-crystal silicon, may be coupled to the light-absorbing layer.

A multijunction solar cell including a growth substrate; a graded interlayer disposed over the growth substrate, a plurality of subcells disposed over the graded interlayer including a second solar subcell disposed over and lattice mismatched with respect to the growth substrate, and at least a third solar subcell disposed over the second subcell; the grading interlayer including a plurality of N step-graded sublayers (where N is an integer and the value of N is 1<N<10), wherein each successive sublayer has an incrementally greater lattice constant than the sublayer below it and grown in such a manner that each sublayer is fully relaxed, a distributed Bragg reflector (DBR) layer over the grading interlayer and an upper solar subcell disposed over the third solar subcell, a band gap in the range of 1.95 to 2.20 eV, and composed of a semiconductor compound including at least indium, aluminum and phosphorus.

Structures including multiple photodiodes and methods of fabricating a structure including multiple photodiodes. A substrate has a first trench extending to a first depth into the substrate and a second trench extending to a second depth into the substrate that is greater than the first depth. A first photodiode includes a first light-absorbing layer containing a first material positioned in the first trench. A second photodiode includes a second light-absorbing layer containing a second material positioned in the second trench. The first material and the second material each include germanium.