Described herein is a semiconductor structure, comprising: a drain region; a drift region comprised of a wide band gap material disposed over the drain region; and a channel structure disposed over the drift region. In some embodiments, the channel structure comprises: an optically active material disposed over the drift region, wherein the optically active material generates charge carriers in response to an optical signal; and a source region disposed over the optically active material, wherein in an off state charge carriers in the optically active material are depleted to turn off the semiconductor structure, and in an on state charge carriers in the optically active material conduct a current in the semiconductor structure when an electric field is applied across the source region and drain region, causing the current to substantially flow directly between the source region and the drain region.

A flexible ultraviolet sensor circuit is provided comprising a number of solar cells, a reflective display device electrically connected to the solar cells, and a floating gate transistor electrically connected to the solar cells and reflective display device. A floating gate in the floating gate transistor discharges in response to ultraviolet light such that the floating gate transistor turns on when a threshold voltage of the floating gate transistor drops below a combined open circuit voltage of the solar cells minus a switching threshold of the reflective display device, thereby causing electrical current flow through the ultraviolet sensor circuit. The reflective display device changes as the electrical current flow increases, indicating total ultraviolet light exposure.

A photodetector includes an insulating layer on a substrate, a first graphene layer on the insulating layer, a 2-dimensional (2D) material layer on the first graphene layer, a second graphene layer on the 2D material layer, a first electrode on the first graphene layer, and a second electrode on the second graphene layer. The 2D material layer includes a barrier layer and a light absorption layer. The barrier layer has a larger bandgap than the light absorption layer.

Example photoconductive devices and example methods for using photoconductive devices are described. An example method may include providing a photoconductive device having a metal-semiconductor-metal structure. The method may also include controlling, based on a first input state, illumination of the photoconductive device by a first optical beam during a time period, and controlling, based on a second input state, illumination of the photoconductive device by a second optical beam during the time period. Further, the method may include detecting an amount of current produced by the photoconductive device during the time period, and based on the detected amount of current, providing an output indicative of the first input state and the second input state. The example devices can be used individually as discrete components or in integrated circuits for memory or logic applications.

An optical device useful for spatial light modulation. The device comprises: a semiconductor layer having a first surface and a second surface, the semiconductor having an electric field-dependent resonance wavelength; a first electrode electrically connected to the semiconductor layer; a first insulating layer adjacent to the first surface of the semiconductor layer, and a second insulating layer adjacent to the second surface of the semiconducting layer, the first and the second insulating layers each being optically transparent at the resonance wavelength; a first group of at least one gate electrodes disposed adjacent to the first insulating layer, and a second group of at least one gate electrodes disposed adjacent to the second insulating layer, each gate electrode being at least 80% optically transparent at the resonance wavelength; wherein the first and the second groups of gate electrodes, taken together, form at least two regions in the semiconductor layer, an electrostatic field in each of the at least two regions being independently controllable by application of voltage to the first and the second groups of gate electrodes, the at least two regions abutting each other along at least one boundary.

An optical device useful for spatial light modulation. The device comprises: a semiconductor layer having a first surface and a second surface, the semiconductor having an electric field-dependent resonance wavelength; a first electrode electrically connected to the semiconductor layer; a first insulating layer adjacent to the first surface of the semiconductor layer, and a second insulating layer adjacent to the second surface of the semiconducting layer, the first and the second insulating layers each being optically transparent at the resonance wavelength; a first group of at least one gate electrodes disposed adjacent to the first insulating layer, and a second group of at least one gate electrodes disposed adjacent to the second insulating layer, each gate electrode being at least 80% optically transparent at the resonance wavelength; wherein the first and the second groups of gate electrodes, taken together, form at least two regions in the semiconductor layer, an electrostatic field in each of the at least two regions being independently controllable by application of voltage to the first and the second groups of gate electrodes, the at least two regions abutting each other along at least one boundary.

A photodetector includes an insulating layer on a substrate, a first graphene layer on the insulating layer, a 2-dimensional (2D) material layer on the first graphene layer, a second graphene layer on the 2D material layer, a first electrode on the first graphene layer, and a second electrode on the second graphene layer. The 2D material layer includes a barrier layer and a light absorption layer. The barrier layer has a larger bandgap than the light absorption layer.

Disclosed herein is a photodetector utilizing graphene. A single-layer graphene channel is formed on a semiconductor substrate doped with n-type impurity. The graphene channel has an end connected to a source electrode and is physically separated from a drain electrode. Light having passed through a gate insulation layer and a gate electrode generates electron-hole pairs at the interface between the graphene channel and the semiconductor substrate forming a Schottky junction, and a photocurrent is generated by a Schottky barrier. In addition, the Schottky barrier is changed according to an applied gate voltage, thereby changing the photocurrent.

Example photoconductive devices and example methods for using photoconductive devices are described. An example method may include providing a photoconductive device having a metal-semiconductor-metal structure. The method may also include controlling, based on a first input state, illumination of the photoconductive device by a first optical beam during a time period, and controlling, based on a second input state, illumination of the photoconductive device by a second optical beam during the time period. Further, the method may include detecting an amount of current produced by the photoconductive device during the time period, and based on the detected amount of current, providing an output indicative of the first input state and the second input state. The example devices can be used individually as discrete components or in integrated circuits for memory or logic applications.

A radiation sensor includes a fin structure including semiconductor material formed on a substrate, a gate formed on an inner side of the fin structure, and a charge collector dielectric layer formed on an outer side of the fin structure.