A photodiode comprises a substrate and a semiconductor stack. The substrate has a major surface. The semiconductor stack is disposed on the major surface. The semiconductor stack includes a buffer layer disposed on the major surface and a light absorption layer disposed on the buffer layer. The light absorption layer is formed of In.sub.xGa.sub.1-xAs.sub.yP.sub.1-y, where x and y are larger than 0 and smaller than 1. The buffer layer is formed of In.sub.zGa.sub.1-zAs, where z is larger than 0 and smaller than 1.

A pixel includes a first doped region of a first conductivity type and a second doped region of a second conductivity type. The first doped region includes first and second layers forming a heterojunction. A dopant concentration of the first layer is greater than a dopant concentration of the second layer. The first layer is made of a semiconductor material and the second layer includes quantum dots. The second doped region is in contact with the second layer, with the first layer being laterally surrounded by an insulated conductive wall that is biased to a negative voltage.

An optical semiconductor device includes: a first semiconductor layer having a first bandgap; and a second semiconductor layer having a second bandgap that is smaller than the first bandgap and formed on the first semiconductor layer. The first semiconductor layer includes a first conductive region with a first polarity, a second conductive region with a second polarity, and a first non-conductive region provided between the first conductive region and the second conductive region. The second semiconductor layer includes a third conductive region with the first polarity, and a second non-conductive region. The third conductive region is in contact with the first conductive region and the first non-conductive region. The second non-conductive region is in contact with at least one of the second conductive region and the first non-conductive region without being in contact with the first conductive region.

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.

The present invention is directed to a position sensing detector made of a photodiode having a semi insulating substrate layer; a buffered layer that is formed directly atop the semi-insulating substrate layer, an absorption layer that is formed directly atop the buffered layer substrate layer, a cap layer that is formed directly atop the absorption layer, a plurality of cathode electrodes electrically coupled to the buffered layer or directly to the cap layer, and at least one anode electrode electrically coupled to a p-type region in the cap layer. The position sensing detector has a photo-response non-uniformity of less than 2% and a position detection error of less than 10 m across the active area.

The present invention pertains to a semiconductor light-receiving element and a method for manufacturing the same, enabling operation in a wide wavelength bandwidth and achieving fast response and high response efficiency. A PIN type photodiode made by sequentially layering on top of the substrate a Si layer of a first conductivity type, a non-doped Ge layer and a Ge layer of a second conductivity type that is the opposite type of the first conductivity type and a Ge current-blocking mechanism is provided in at least part of the periphery of the PIN type photodiode.

A detector for detecting single photons of infrared radiation. In one embodiment a waveguide configured to transmit infrared radiation is arranged to be adjacent a graphene sheet and configured so that evanescent waves from the waveguide overlap the graphene sheet. An infrared photon absorbed by the graphene sheet from the evanescent waves heats the graphene sheet. The graphene sheet is coupled to the weak link of a Josephson junction, and a constant bias current is driven through the Josephson junction, so that an increase in the temperature of the graphene sheet results in a decrease in the critical current of the Josephson junction and a voltage pulse in the voltage across the Josephson junction. The voltage pulse is detected by the pulse detector.

An optical communication system includes an optical waveguide and a photodetector (PD). The optical waveguide is arranged to receive and guide an optical signal. The PD is configured to receive the optical signal from the optical waveguide and to convert the optical signal into an electrical signal. The PD includes a stack of layers including at least (i) first layers including two or more semiconductor layers forming a reverse-biased semiconductor junction configured to produce the electrical signal in response to the optical signal impinging thereon, and (ii) second layers forming a capacitance component that in is connected with series the reverse-biased semiconductor junction. The PD further includes a first electrode and a second electrode, configured to (i) apply one or more voltages that reverse-bias the reverse-biased semiconductor junction and (ii) output the electrical signal.

A semiconductor layered structure according to the present invention includes a substrate formed of a III-V compound semiconductor; and semiconductor layers disposed on the substrate and formed of III-V compound semiconductors. The substrate has a majority-carrier-generating impurity concentration of 110.sup.17 cm.sup.3 or more and 210.sup.20 cm.sup.3 or less, and the impurity has an activation ratio of 30% or more.

An optoelectronic device as well as its methods of use and manufacture are disclosed. In one embodiment, an optoelectronic device includes first and second semiconducting atomically thin layers with corresponding first and second lattice directions. The first and second semiconducting atomically thin layers are located proximate to each other, and an angular difference between the first lattice direction and the second lattice direction is between about 0.000001 and 0.5, or about 0.000001 and 0.5 deviant from of a Vicnal angle of the first and second semiconducting atomically thin layers. Alternatively, or in addition to the above, the first and second semiconducting atomically thin layers may form a Moir superlattice of exciton funnels with a period between about 50 nm to 3 cm. The optoelectronic device may also include charge carrier conductors in electrical communication with the semiconducting atomically thin layers to either inject or extract charge carriers.