Optically sensitive devices include a device comprising a first contact and a second contact, each having a work function, and an optically sensitive material between the first contact and the second contact. The optically sensitive material comprises a p-type semiconductor, and the optically sensitive material has a work function. Circuitry applies a bias voltage between the first contact and the second contact. The optically sensitive material has an electron lifetime that is greater than the electron transit time from the first contact to the second contact when the bias is applied between the first contact and the second contact. The first contact provides injection of electrons and blocking the extraction of holes. The interface between the first contact and the optically sensitive material provides a surface recombination velocity less than 1 cm/s.

A photo-sensing unit including a first electrode, a first insulation layer, a photo-sensing structure and a second electrode is provided. The first insulation layer covers the first electrode and has an opening exposing the first electrode. The photo-sensing structure is located on the first electrode and disposed in the opening of the first insulation layer. The photo-sensing structure includes a first photo-sensing layer and a second photo-sensing layer stacked with each other. A material of the first photo-sensing layer is Si.sub.xGe.sub.yO.sub.z. A material of the second photo-sensing layer is Si.sub.vO.sub.w. The second electrode covers the photo-sensing structure. A photo-sensing apparatus including the photo-sensing unit and a fabricating method of a photo-sensing unit are also provided.

A semiconductor device is disclosed, which includes: at least one device layer being a crystallized layer for example including: a superlattice layer and/or a layer of group III-V semiconductor materials; and a passivation structure comprising one or more layers wherein at least one layer of the passivation structure is a passivation layer grown in-situ in a crystallized form on top of the device layer, and at least one of the one or more layers of the passivation structure includes material having a high density of surface states which forces surface pinning of an equilibrium Fermi level within a certain band gap of the device layer, away from its conduction and valence bands.

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 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 photodiode includes a light absorbing layer including a first superlattice structure that includes first semiconductor layers and second semiconductor layers, the first superlattice structure having a band structure sensitive to infrared light; a p-type semiconductor region; and an intermediate layer disposed between the p-type semiconductor region and the light absorbing layer, the intermediate layer having a conduction band having a bottom energy level lower than that of the p-type semiconductor region.

A method for growing on a substrate strongly aligned uniform cross-section semiconductor composite nanocolumns is disclosed. The method includes: (a) forming faceted pyramidal pits on the substrate surface; (b) initiating nucleation on the facets of the pits; and; (c) promoting the growth of nuclei toward the center of the pits where they coalesce with twinning and grow afterwards together as composite nanocolumns. Multi-quantum-well, core-shell nanocolumn heterostructures can be grown on the sidewalls of the nanocolumns. Furthermore, a continuous semiconductor epitaxial layer can be formed through the overgrowth of the nanocolumns to facilitate fabrication of high-quality planar device structures or for light emitting structures.

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.

Various particular embodiments include a method for forming a photodetector, including: forming a structure including a barrier layer disposed between a layer of doped silicon (Si) and a layer of germanium (Ge), the barrier layer including a crystallization window; and annealing the structure to convert, via the crystallization window, the Ge to a first composition of silicon germanium (SiGe) and the doped Si to a second composition of SiGe.

A transducer to convert optical energy to electrical energy. The transducer or photo-transducer has a base layer which has a group of connecting elements formed therein at separations which are increasing with the distance away from an emitter layer formed atop the base layer. The connecting elements separate and electrically connect the base layer into base segments, the base segments having increasing thicknesses with the distance away from the emitter layer. The photo-transducer generates an output voltage that is greater than the input light photovoltage. The photo-transducer output voltage is proportional to the number of connecting elements formed in the base layer.