A dual-band infrared detector is provided. The dual-band infrared detector includes a first absorption layer sensitive to radiation in only a short wavelength infrared spectral band, and a barrier layer coupled to the first absorption layer. The barrier layer is fabricated from an alloy including aluminum and antimony, and at least one of gallium or arsenic. The dual-band infrared detector also includes a second absorption layer coupled to the barrier layer opposite the first absorption layer. The second absorption layer is sensitive to radiation in only a medium wavelength infrared spectral band. The composition of the alloy used to fabricate the barrier layer is selected such that valence bands of the barrier layer and the first and second absorption layers substantially align.

An infrared detector is provided. The infrared detector includes an absorption layer sensitive to radiation in only a short wavelength infrared spectral band, and a barrier layer coupled to the absorption layer. The barrier layer is fabricated from an alloy including aluminum and antimony, and at least one of gallium or arsenic, and the composition of the alloy is selected such that valence bands of the absorption layer and the barrier layer substantially align.

A photodetector includes a photodiode that has a germanium junction formed between an n-doped region and a p-doped region. The germanium junction is formed to have an input interface at a light input end of the germanium junction. The input interface has a substantially flat shape or a convex-faceted shape. The photodetector also includes an input waveguide connected to the input interface of the germanium junction. The input waveguide has a substantially linear shape along a lengthwise centerline of the input waveguide. The input waveguide is oriented so that the lengthwise centerline of the input waveguide is positioned at a non-zero angle relative to input interface of the germanium junction.

A radiation detector includes a stack of layers along a direction Z, the stack comprising: an absorbent layer, a first contact layer, an assembly consisting of at least one intermediate layer, referred to as an intermediate assembly, an upper layer, the first contact layer and the upper layer having a plurality of detection zones and separation zones, a detection zone corresponding to a pixel of the detector, a passivation layer made from a dielectric material, arranged on the upper layer and having openings at the level of the detection zones of the upper layer, the semiconductor layers of the stack being compounds based on elements of groups IIIA and VA of the periodic table of the elements, the second material comprising the VA element antimony and the third material not comprising the VA element antimony.

A radiation detector includes a stack of layers along a direction Z, the stack comprising: an absorbent layer, a first contact layer, an assembly consisting of at least one intermediate layer, referred to as an intermediate assembly, an upper layer, the first contact layer and the upper layer having a plurality of detection zones and separation zones, a detection zone corresponding to a pixel of the detector, a passivation layer made from a dielectric material, arranged on the upper layer and having openings at the level of the detection zones of the upper layer, the semiconductor layers of the stack being compounds based on elements of groups IIIA and VA of the periodic table of the elements, the second material comprising the VA element antimony and the third material not comprising the VA element antimony.

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. In some embodiments the waveguide is omitted and infrared light propagating in free space illuminates the graphene sheet directly. A 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.

According to embodiments of the present invention, a photodetector arrangement is provided. The photodetector arrangement includes a plurality of germanium-based photodetectors, each germanium-based photodetector configured to receive an optical signal and to generate an electrical signal in response to the received optical signal, and an electrode arrangement arranged to conduct the electrical signals.

A method of fabricating a diode includes forming a first semiconductor layer having a first portion and a second portion extending from the first portion on a substrate; forming first and second electrodes on the substrate, the first electrode extending over and being in contact with the first portion of the first semiconductor layer; forming an insulting film to cover the first electrode and the first portion of the first semiconductor layer; and forming a second semiconductor layer having a first portion and a second portion extending from the first portion on the substrate. The second portion of the second semiconductor layer overlapping with the second portion of the first semiconductor layer to define a vertically stacked heterojunction therewith. The first portion of the second semiconductor layer extending over and being in contact with the second electrode. Each of the first and second semiconductor layers includes an atomically thin semiconductor.

The subject matter disclosed herein relates to formation of silicon germanium devices with tensile strain. Tensile strain applied to a silicon germanium device in fabrication may improve performance of a silicon germanium laser or light detector.

A semiconductor optical device includes a semiconductor substrate having first to fourth regions, a 90-degree optical hybrid provided in the third region on a principal surface of the semiconductor substrate, first and second waveguides provided in the first region being optically coupled to the 90-degree optical hybrid, a photodiode provided in the fourth region, a third waveguide provided in the second region to optically couple the 90-degree optical hybrid to the photodiode, and a metal layer provided on a back surface of the semiconductor substrate. The metal layer includes a first part provided in the first region and a second part provided in the second region spaced apart from the first region by a distance. The 90-degree optical hybrid has a first length. The distance between the first and second parts is more than or equal to the first length.