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 semiconductor device is disclosed, which includes: at least one a 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.

Embodiments of the present disclosure are directed to infrared detector devices incorporating a tunneling structure. In one embodiment, an infrared detector device includes a first contact layer, an absorber layer adjacent to the first contact layer, and a tunneling structure including a barrier layer adjacent to the absorber layer and a second contact layer adjacent to the barrier layer. The barrier layer has a tailored valence band offset such that a valence band offset of the barrier layer at the interface between the absorber layer and the barrier layer is substantially aligned with the valence band offset of the absorber layer, and the valence band offset of the barrier layer at the interface between the barrier layer and the second contact layer is above a conduction band offset of the second contact layer.

A photoconductor includes a first semiconductor layer, a second semiconductor layer disposed on the first semiconductor layer, a first electrode connected to a first lateral side of the first semiconductor layer and the second semiconductor layer, and a second electrode connected to a second lateral side of the first semiconductor layer and the second semiconductor layer, where the first semiconductor layer and the second semiconductor layer form a type II junction or a quasi-type-II junction.

The present invention relates to a semiconductor photosensitive unit and a semiconductor photosensitive unit array thereof, including a floating gate transistor, a gating MOS transistor and a photodiode that are disposed on a semiconductor substrate. An anode or a cathode of the photodiode is connected to a floating gate of the floating gate transistor through the gating MOS transistor, and the corresponding cathode or anode of the photodiode is connected to a drain of the floating gate transistor or connected to an external electrode. After the gating MOS transistor is switched on, the floating gate is charged or discharged through the photodiode; and after the gating MOS transistor is switched off, charges are stored in the floating gate of the floating gate transistor. Advantages like a small unit area, low surface noise, long charge storage time of the floating gate, and large dynamic range of an operating voltage are achieved.

Embodiments of the invention describe apparatuses, optical systems, and methods related to utilizing optical cladding layers. According to one embodiment, a hybrid optical device includes a silicon semiconductor layer and a III-V semiconductor layer having an overlapping region, wherein a majority of a field of an optical mode in the overlapping region is to be contained in the III-V semiconductor layer. A cladding region between the silicon semiconductor layer and the III-V semiconductor layer has a spatial property to substantially confine the optical mode to the III-V semiconductor layer and enable heat dissipation through the silicon semiconductor layer.

According to example embodiments, a two-dimensional (2D) material element may include a first 2D material and a second 2D material chemically bonded to each other. The first 2D material may include a first metal chalcogenide-based material. The second 2D material may include a second metal chalcogenide-based material. The second 2D material may be bonded to a side of the first 2D material. The 2D material element may have a PN junction structure. The 2D material element may include a plurality of 2D materials with different band gaps.

An object is to provide an infrared sensor with a quantum dot optimized. The present invention provides an infrared sensor (1) including a light absorption layer (5) that absorbs an infrared ray, wherein the light absorption layer includes a plurality of spherical quantum dots (21). Alternatively, the present invention provides an infrared sensor including a light absorption layer that absorbs an infrared ray, wherein the light absorption layer includes a plurality of quantum dots and the quantum dot includes at least one kind of PbS, PbSe, CdHgTe, Ag.sub.2S, Ag.sub.2Se, Ag.sub.2Te, AgInSe.sub.2, AgInTe.sub.2, CuInSe.sub.2, CuInTe.sub.2, and InAs.

There is disclosed an ultraviolet (UV) photo sensing element comprising a GaN substrate and a Ta.sub.2O.sub.5 thin film layer, forming a GaN (gallium-nitride) and Ta.sub.2O.sub.5 (tantalum pentoxide) based heterojunction wherein the formed heterojunction receives and converts UV light into electrical signals/in the photovoltaic mode (at 0 V) or in a self-driven mode. Also disclosed is a method of fabrication of an ultraviolet (UV) photodetector (PD) device, the method comprising growing silicon-doped n-type GaN epitaxial layers on a stack of un-doped GaN/sapphire samples, cleaning the GaN samples, pelletizing and depositing tantalum pentoxide (Ta.sub.2O.sub.5) powder on the n-type GaN samples, forming Ta.sub.2O.sub.5/GaN stacks, post-annealing the formed Ta.sub.2O.sub.5/GaN stacks; and depositing high purity Au on the Ta.sub.2O.sub.5/GaN stacks. The photodetector (PD) device is a heterojunction ultraviolet (UV) photodetector (PD) device.

There is disclosed an ultraviolet (UV) photo sensing element comprising a GaN substrate and a Ta.sub.2O.sub.5 thin film layer, forming a GaN (gallium-nitride) and Ta.sub.2O.sub.5 (tantalum pentoxide) based heterojunction wherein the formed heterojunction receives and converts UV light into electrical signals/in the photovoltaic mode (at 0 V) or in a self-driven mode. Also disclosed is a method of fabrication of an ultraviolet (UV) photodetector (PD) device, the method comprising growing silicon-doped n-type GaN epitaxial layers on a stack of un-doped GaN/sapphire samples, cleaning the GaN samples, pelletizing and depositing tantalum pentoxide (Ta.sub.2O.sub.5) powder on the n-type GaN samples, forming Ta.sub.2O.sub.5/GaN stacks, post-annealing the formed Ta.sub.2O.sub.5/GaN stacks; and depositing high purity Au on the Ta.sub.2O.sub.5/GaN stacks. The photodetector (PD) device is a heterojunction ultraviolet (UV) photodetector (PD) device.