A light sensor includes a lower electrode layer, an absorption layer and an upper electrode layer. The absorption layer is located on the lower electrode layer, in which the absorption layer includes a material that has an electron mobility greater than 300 cm.sup.2/Vs and greater than twice as many as a hole mobility. The upper electrode layer is located on the absorption layer, and is configured to collect the scattered high-speed excess electrons and to leave low-speed excess holes near the edges of the upper electrode layer. A downward photocurrent is generated by the photovoltage in the absorption layer due to the formation of positively charged region near the upper surface.

A photodetector includes a first semiconductor layer including germanium, a conductive layer that, in conjunction with the first semiconductor layer, forms a Schottky junction structure, and a tunneling barrier layer positioned between the first semiconductor layer and the conductive layer and configured to prevent dark current between the first semiconductor layer and the conductive layer.

An avalanche photodiode detector is provided. The avalanche photodiode detector comprises an absorber region having an absorption layer for receiving incident photons and generating charged carriers; and a multiplier region having a multiplication layer; wherein the multiplier region is on a mesa structure separate from the absorber region and is coupled to the absorber region by a bridge for transferring charged carriers between the absorber region and multiplier region.

A Schottky barrier diode includes a first semiconductor layer, a LOCOS layer arranged in contact with the first semiconductor layer, a Schottky junction region provided on a contact surface between the first semiconductor layer and a first electrode, a second semiconductor layer connected to the first semiconductor layer and having a higher carrier concentration than that of the first semiconductor layer, and a second electrode forming an ohmic contact with the second semiconductor layer. In this case, the Schottky junction region and the LOCOS layer are in contact.

A semiconductor device for a system for measuring temperature, which includes a first UV detector and a second UV detector. The first and second UV detectors generate a first current and a second current, respectively, as a function of the irradiance in the ultraviolet band. Moreover, the first and second UV detectors have coefficients of variation of the current with temperature, at constant irradiance, that are different from one another.

Electromagnetic wave detector includes semiconductor layer, first insulating film, two-dimensional material layer, first electrode, second electrode, second insulating film, and control electrode. First insulating film is arranged on semiconductor layer. First insulating film is provided with opening. Two-dimensional material layer is electrically connected to semiconductor layer in opening. Two-dimensional material layer extends from above opening to first insulating film. Second insulating film is in contact with two-dimensional material layer. Control electrode is connected to two-dimensional material layer with second insulating film interposed therebetween.

Electromagnetic wave detector includes semiconductor layer, first insulating film, two-dimensional material layer, first electrode, second electrode, second insulating film, and control electrode. First insulating film is arranged on semiconductor layer. First insulating film is provided with opening. Two-dimensional material layer is electrically connected to semiconductor layer in opening. Two-dimensional material layer extends from above opening to first insulating film. Second insulating film is in contact with two-dimensional material layer. Control electrode is connected to two-dimensional material layer with second insulating film interposed therebetween.

A UVC Metal-Semiconductor-Metal photodetector with metallic contacts made of Ni and/or Au and/or Ti, characterized in that the photodetector comprises an aluminum alloy with Ga2O3, providing a broadened and/or shifted spectral response toward shorter wavelengths compared to a Ga2O3-only based detector. The invention also relates to an imaging system based on a UVC focal plane array with a network of MSM photodetectors with metallic contacts made of Ni and/or Au and/or Ti, based on (Al)Ga2O3, for remote detection/location/optical imaging of a fire, corona discharge, missile launch, ozone hole monitoring, or gas detection. The invention also relates to MSM UVC photodetectors designed on a substrate that is transparent in the UVC, allowing back-illumination to facilitate the manufacturing of flip-chip devices with higher efficiency compared to front-illuminated detectors by avoiding light reflections from the front surface metallic contacts.

The invention provides a silicon-based room-temperature infrared hot-electron photodetector, preparation method and use thereof. The photodetector includes a base and a planar multi-layer structure. The planar multi-layer structure includes a bottom conductive electrode, a silicon film, a transition metal film, and a transparent dielectric film. The electrode and the silicon film form an ohmic contact and constitute an optical reflector. The silicon film and the transition metal film form a Schottky contact, the thickness of the silicon film is smaller than the depletion layer width of a Schottky junction formed by the silicon film and the transition metal film, the transition metal film absorbs near infrared light and generates hot electrons to be injected into the silicon film, and the hot electrons are collected by the electrode to form a photocurrent. The transparent dielectric film is used as an antireflection layer and can reduce reflection of incident light.

Provided is an ultraviolet light receiving device having photosensitivity effective to target wavelengths in the ultraviolet region. A Schottky junction ultraviolet light receiving device has the photosensitivity peak wavelength in an ultraviolet region of 230 nm or more and 320 nm or less, and exhibits a rejection ratio of 10.sup.5 or more, the rejection ratio being the ratio of the responsivity Rp to the peak photosensitivity wavelength to the average of the responsivity Rv to a visible region of 400 nm or more and 680 nm or less (Rp/Rv).