Abstract: A light emitting device includes a substrate, multiple n-type layers, and multiple p-type layers. The n-type layers and the p-type layers each include a group III nitride alloy. At least one of the n-type layers is a compositionally graded n-type group III nitride, and at least one of the p-type layers is a compositionally graded p-type group III nitride. A first ohmic contact for injecting current is formed on the substrate, and a second ohmic contact is formed on a surface of at least one of the p-type layers. Utilizing the disclosed structure and methods, a device capable of emitting light over a wide spectrum may be made without the use of phosphor materials.

Abstract: An ultraviolet light sensor and method of manufacturing thereof are disclosed. The ultraviolet light sensor includes Group-III Nitride layers adjacent to a silicon wafer with one of the layers at least partially exposed such that a surface thereof can receive UV light to be detected. The Group-III Nitride layers include a p-type layer and an n-type layer, with p/n junctions therebetween forming at least one diode. Conductive contacts are arranged to conduct electrical current through the sensor as a function of ultraviolet light received at the outer Group-III Nitride layer. The Group-III Nitride layers may be formed from, e.g., GaN, InGaN, AlGaN, or InAlN. The sensor may include a buffer layer between one of the Group-III Nitride layers and the silicon wafer. By utilizing silicon as the substrate on which the UV sensor diode is formed, a UV sensor can be produced that is small, efficient, cost-effective, and compatible with other semiconductor circuits and processes.

Abstract: A light emitting device includes a substrate, multiple n-type layers, and multiple p-type layers. The n-type layers and the p-type layers each include a group III nitride alloy. At least one of the n-type layers is a compositionally graded n-type group III nitride, and at least one of the p-type layers is a compositionally graded p-type group III nitride. A first ohmic contact for injecting current is formed on the substrate, and a second ohmic contact is formed on a surface of at least one of the p-type layers. Utilizing the disclosed structure and methods, a device capable of emitting light over a wide spectrum may be made without the use of phosphor materials.

Abstract: An ultraviolet light sensor and method of manufacturing thereof are disclosed. The ultraviolet light sensor includes Group-III Nitride layers adjacent to a silicon wafer with one of the layers at least partially exposed such that a surface thereof can receive UV light to be detected. The Group-III Nitride layers include a p-type layer and an n-type layer, with p/n junctions therebetween forming at least one diode. Conductive contacts are arranged to conduct electrical current through the sensor as a function of ultraviolet light received at the outer Group-III Nitride layer. The Group-III Nitride layers may be formed from, e.g., GaN, InGaN, AlGaN, or InAlN. The sensor may include a buffer layer between one of the Group-III Nitride layers and the silicon wafer. By utilizing silicon as the substrate on which the UV sensor diode is formed, a UV sensor can be produced that is small, efficient, cost-effective, and compatible with other semiconductor circuits and processes.

Abstract: An ultraviolet light sensor and method of manufacturing thereof are disclosed. The ultraviolet light sensor includes Group-III Nitride layers adjacent to a silicon wafer with one of the layers at least partially exposed such that a surface thereof can receive UV light to be detected. The Group-III Nitride layers include a p-type layer and an n-type layer, with p/n junctions therebetween forming at least one diode. Conductive contacts are arranged to conduct electrical current through the sensor as a function of ultraviolet light received at the outer Group-III Nitride layer. The Group-III Nitride layers may be formed from, e.g., GaN, InGaN, AlGaN, or InAlN. The sensor may include a buffer layer between one of the Group-III Nitride layers and the silicon wafer. By utilizing silicon as the substrate on which the UV sensor diode is formed, a UV sensor can be produced that is small, efficient, cost-effective, and compatible with other semiconductor circuits and processes.

Abstract: An ultraviolet light sensor and method of manufacturing thereof are disclosed. The ultraviolet light sensor includes Group-III Nitride layers adjacent to a silicon wafer with one of the layers at least partially exposed such that a surface thereof can receive UV light to be detected. The Group-III Nitride layers include a p-type layer and an n-type layer, with p/n junctions therebetween forming at least one diode. Conductive contacts are arranged to conduct electrical current through the sensor as a function of ultraviolet light received at the outer Group-III Nitride layer. The Group-III Nitride layers may be formed from, e.g., GaN, InGaN, AlGaN, or InAlN. The sensor may include a buffer layer between one of the Group-III Nitride layers and the silicon wafer. By utilizing silicon as the substrate on which the UV sensor diode is formed, a UV sensor can be produced that is small, efficient, cost-effective, and compatible with other semiconductor circuits and processes.

Abstract: A photovoltaic device having three dimensional (3D) charge separation and collection, where charge separation occurs in 3D depletion regions formed between a p-type doped group III-nitride material in the photovoltaic device and intrinsic structural imperfections extending through the material. The p-type group III-nitride alloy is compositionally graded to straddle the Fermi level pinning by the intrinsic structural imperfections in the material at different locations in the group III-nitride alloy. A field close to the surfaces of the intrinsic defects separates photoexcited electron-hole pairs and drives the separated electrons to accumulate at the surfaces of the intrinsic defects. The intrinsic defects function as n-type conductors and transport the accumulated electrons to the material surface for collection. The compositional grading also creates a potential that drives the accumulated separated electrons toward an n-type group III-nitride layer for collection.

Abstract: Here we present an apparatus comprising a photoelectrochemical cell connected a photovoltaic device, comprised of a layer with a thick n-type absorber and a layer comprising a thin p-type hole emitter. The photoelectrochemical cell has binary, metal-oxide semiconductors with wide bandgaps comprising high electron affinities relative to other semiconductor materials allowing for n-type doping.

Abstract: A light emitting device includes a substrate, multiple n-type layers, and multiple p-type layers. The n-type layers and the p-type layers each include a group III nitride alloy. At least one of the n-type layers is a compositionally graded n-type group III nitride, and at least one of the p-type layers is a compositionally graded p-type group III nitride. A first ohmic contact for injecting current is formed on the substrate, and a second ohmic contact is formed on a surface of at least one of the p-type layers. Utilizing the disclosed structure and methods, a device capable of emitting light over a wide spectrum may be made without the use of phosphor materials.

Abstract: This disclosure provides systems, methods, and apparatus related to thermoelectric materials. In one aspect, a thermoelectric material is provided. The thermoelectric material is then irradiated with charged particles to generated native defects in the thermoelectric material. The charged particles have energies of 100 keV or greater. The irradiation of the thermoelectric material may improve its thermoelectric properties.

Abstract: A light emitting device includes a substrate, multiple n-type layers, and multiple p-type layers. The n-type layers and the p-type layers each include a group III nitride alloy. At least one of the n-type layers is a compositionally graded n-type group III nitride, and at least one of the p-type layers is a compositionally graded p-type group III nitride. A first ohmic contact for injecting current is formed on the substrate, and a second ohmic contact is formed on a surface of at least one of the p-type layers. Utilizing the disclosed structure and methods, a device capable of emitting light over a wide spectrum may be made without the use of phosphor materials.

Abstract: A light emitting device includes a substrate, multiple n-type layers, and multiple p-type layers. The n-type layers and the p-type layers each include a group III nitride alloy. At least one of the n-type layers is a compositionally graded n-type group III nitride, and at least one of the p-type layers is a compositionally graded p-type group III nitride. A first ohmic contact for injecting current is formed on the substrate, and a second ohmic contact is formed on a surface of at least one of the p-type layers. Utilizing the disclosed structure and methods, a device capable of emitting light over a wide spectrum may be made without the use of phosphor materials.

Abstract: An intermediate band solar cell (IBSC) is provided including a p-n junction based on dilute III-V nitride materials and a pair of contact blocking layers positioned on opposite surfaces of the p-n junction for electrically isolating the intermediate band of the p-n junction by blocking the charge transport in the intermediate band without affecting the electron and hole collection efficiency of the p-n junction, thereby increasing open circuit voltage (VOC) of the IBSC and increasing the photocurrent by utilizing the intermediate band to absorb photons with energy below the band gap of the absorber layers of the IBSC. Hence, the overall power conversion efficiency of a IBSC will be much higher than an conventional single junction solar cell. The p-n junction absorber layers of the IBSC may further have compositionally graded nitrogen concentrations to provide an electric field for more efficient charge collection.

Abstract: A light emitting device includes a substrate, multiple n-type layers, and multiple p-type layers. The n-type layers and the p-type layers each include a group III nitride alloy. At least one of the n-type layers is a compositionally graded n-type group III nitride, and at least one of the p-type layers is a compositionally graded p-type group III nitride. A first ohmic contact for injecting current is formed on the substrate, and a second ohmic contact is formed on a surface of at least one of the p-type layers. Utilizing the disclosed structure and methods, a device capable of emitting light over a wide spectrum may be made without the use of phosphor materials.

Abstract: An intermediate band solar cell (IBSC) is provided including a p-n junction based on dilute III-V nitride materials and a pair of contact blocking layers positioned on opposite surfaces of the p-n junction for electrically isolating the intermediate band of the p-n junction by blocking the charge transport in the intermediate band without affecting the electron and hole collection efficiency of the p-n junction, thereby increasing open circuit voltage (VOC) of the IBSC and increasing the photocurrent by utilizing the intermediate band to absorb photons with energy below the band gap of the absorber layers of the IBSC. Hence, the overall power conversion efficiency of a IBSC will be much higher than an conventional single junction solar cell. The p-n junction absorber layers of the IBSC may further have compositionally graded nitrogen concentrations to provide an electric field for more efficient charge collection.

Abstract: A single junction solar cell may be manufactured with a material having multiple bands. That is, a single semiconductor with several absorption edges that absorb photons from different parts of the solar spectrum may be constructed. The different absorption edges may be created by splitting a conduction band of the solar cell material into multiple intermediate sub-bands. The solar cell may include a photovoltaic material deposited on a substrate, in which the photovoltaic material is a III-V semiconductor alloy, such as AlGaNAs, AlGaAsNSb, or AlInGaNAsBi.

Abstract: A new composition of matter is described, amorphous GaN1-xAsx:Mg, wherein 0<x<1, and more preferably 0.1<x<0.8, which amorphous material is of low resistivity, and when formed as a thin, heavily doped film may be used as a low resistant p-type ohmic contact layer for a p-type group III-nitride layer in such applications as photovoltaic cells. The layer may be applied either as a conformal film or a patterned layer. In one embodiment, as a lightly doped but thicker layer, the amorphous GaN1-xAsx:Mg film can itself be used as an absorber layer in PV applications. Also described herein is a novel, low temperature method for the formation of the heavily doped amorphous GaN1-xAsx:Mg compositions of the invention in which the doping is achieved during film formation according to MBE methods.

Abstract: A light emitting device includes a substrate, multiple n-type layers, and multiple p-type layers. The n-type layers and the p-type layers each include a group III nitride alloy. At least one of the n-type layers is a compositionally graded n-type group III nitride, and at least one of the p-type layers is a compositionally graded p-type group III nitride. A first ohmic contact for injecting current is formed on the substrate, and a second ohmic contact is formed on a surface of at least one of the p-type layers. Utilizing the disclosed structure and methods, a device capable of emitting light over a wide spectrum may be made without the use of phosphor materials.

Abstract: An intermediate band solar cell (IBSC) is provided including a p-n junction based on dilute III-V nitride materials and a pair of contact blocking layers positioned on opposite surfaces of the p-n junction for electrically isolating the intermediate band of the p-n junction by blocking the charge transport in the intermediate band without affecting the electron and hole collection efficiency of the p-n junction, thereby increasing open circuit voltage (VOC) of the IBSC and increasing the photocurrent by utilizing the intermediate band to absorb photons with energy below the band gap of the absorber layers of the IBSC. Hence, the overall power conversion efficiency of a IBSC will be much higher than an conventional single junction solar cell. The p-n junction absorber layers of the IBSC may further have compositionally graded nitrogen concentrations to provide an electric field for more efficient charge collection.

Abstract: An intermediate band solar cell (IBSC) is provided including a p-n junction based on dilute III-V nitride materials and a pair of contact blocking layers positioned on opposite surfaces of the p-n junction for electrically isolating the intermediate band of the p-n junction by blocking the charge transport in the intermediate band without affecting the electron and hole collection efficiency of the p-n junction, thereby increasing open circuit voltage (VOC) of the IBSC and increasing the photocurrent by utilizing the intermediate band to absorb photons with energy below the band gap of the absorber layers of the IBSC. Hence, the overall power conversion efficiency of a IBSC will be much higher than an conventional single junction solar cell. The p-n junction absorber layers of the IBSC may further have compositionally graded nitrogen concentrations to provide an electric field for more efficient charge collection.