Abstract: A heterostructure device or article includes a carrier transport layer, a back channel layer and a barrier layer. The carrier transport layer has a first surface and a second surface opposing to the first surface. The back channel layer is secured to the first surface of the carrier transport layer and the barrier layer is secured to the second surface of the carrier transport layer. Each of the carrier transport layer, the back channel layer and the barrier layer comprises an aluminum gallium nitride alloy. The article further includes a 2D electron gas at an interface of the second surface of the carrier transport layer and a surface of the barrier layer. The 2D electron gas is defined by a bandgap differential at an interface, which allows for electron mobility. A system includes a heterostructure field effect transistor that includes the article.

Abstract: A sensor system for measuring a plurality of chemical species is disclosed. The sensor system includes a plurality of semiconductor device sensor elements, wherein each sensor element includes at least one wide band gap semiconductor layer and at least one catalytic layer configured to have an electrical property modifiable on exposure to an analyte including one or more chemical species; and an acquisition and analysis system configured to receive sensor signals from the plurality of sensor elements and to use multivariate analysis techniques to analyze the sensor signals to provide multivariate analyte measurement data.

Abstract: Gallium oxide films for sensing gas comprise Ga2O3 and have a porosity of at least about 30%. Such films can be formed by coating a substrate with a solution comprising: a gallium salt and a porogen comprising an organic compound comprising a hydrophilic chain and a hydrophobic chain; and heating the substrate to a temperature in the range from about 400° C. to about 600° C. while exposing the substrate to an oxygen-containing source to convert the gallium salt to a gallium oxide.

Abstract: The invention is directed to a method for optical and electrical isolation between adjacent integrated devices. The method comprises the steps of forming at least one trench through an exposed surface of a semiconductor wafer by removing a portion of the semiconductor wafer material, forming an electrically insulating layer on the sidewalls and the bottom of the at least one trench, filling the at least one trench by conformally depositing an optically isolating material, and planarizing the semiconductor wafer surface by removing the portion of the optically isolating material above the exposed surface of the semiconductor wafer.

Abstract: There is provided a GaN single crystal at least about 2.75 millimeters in diameter, with a dislocation density less than about 104 cm?1, and having substantially no tilt boundaries. A method of forming a GaN single crystal is also disclosed. The method includes providing a nucleation center, a GaN source material, and a GaN solvent in a chamber. The chamber is pressurized. First and second temperature distributions are generated in the chamber such that the solvent is supersaturated in the nucleation region of the chamber. The first and second temperature distributions have different temperature gradients within the chamber.

Abstract: The present invention is directed toward a method for fabricating low-defect nanostructures of wide bandgap materials and to optoelectronic devices, such as light emitting sources and lasers, based on them. The invention utilizes nanolithographically-defined templates to form nanostructures of wide bandgap materials that are energetically unfavorable for dislocation formation. In particular, this invention provides a method for the fabrication of phosphor-less monolithic white light emitting diodes and laser diodes that can be used for general illumination and other applications.

Abstract: A GaN crystal having up to about 5 mole percent of at least one of aluminum, indium, and combinations thereof. The GaN crystal has at least one grain having a diameter greater than 2 mm, a dislocation density less than about 104 cm?2, and is substantially free of tilt boundaries.

Abstract: A gas sensor device including a semiconductor substrate; one or more catalytic gate-electrodes deposited on a surface of the semiconductor substrate; one or more ohmic contacts deposited on the surface of the semiconductor substrate and a passivation layer deposited on at least a portion of the surface; wherein the semiconductor substrate includes a material selected from the group consisting of silicon carbide, diamond, Group III nitrides, alloys of Group III nitrides, zinc oxide, and any combinations thereof.

Abstract: An ultraviolet sensor monitors an effectiveness of ultraviolet lamps used in sterilization systems. The sensor includes an ultraviolet photodetector and a filter cooperating therewith configured for detecting light at wavelengths between 200-300 nm. A purification system for air or water utilizes the sensor in conjunction with an ultraviolet lamp directing ultraviolet light toward the air or water.

Abstract: There is provided a GaN single crystal at least about 2 millimeters in diameter, with a dislocation density less than about 104 cm−1, and having no tilt boundaries. A method of forming a GaN single crystal is also disclosed. The method includes providing a nucleation center, a GaN source material, and a GaN solvent in a chamber. The chamber is pressurized. First and second temperature distributions are generated in the chamber such that the solvent is supersaturated in the nucleation region of the chamber. The first and second temperature distributions have different temperature gradients within the chamber.