Abstract: Sensors for sensing/measuring one or more analytes in a chemical environment. Each sensor is based on a semiconductor structure having an interfacial region containing a two-dimensional electron gas (2DEG). A catalyst reactive to the analyte(s) is in contact with the semiconductor structure. Particles stripped from the analyte(s) by the catalyst passivate the surface of the semiconductor structure at the interface between the catalyst and the structure, thereby causing the charge density in the 2DEG proximate the catalyst to change. When this basic structure is incorporated into an electronic device, such as a high-electron-mobility transistor (HEMT) or a Schottky diode, the change in charge density manifests into a change in an electrical response of the device. For example, in an HEMT, the change in charge density manifests as a change in current through the transistor, and, in a Schottky diode, the change in charge density manifests as a change in capacitance.

Abstract: Methods and systems to determine a concentration of bromide ions in an aqueous sample are disclosed. The method involves the oxidation of bromide ions to bromine, followed by bromination of a colored or fluorescent reporter compound which may be detected by spectrophotometric means. The relative change in color or fluorescence upon bromine binding to the reporter compound may then be used to determine a quantitative concentration of bromide ions in the sample. The system utilizes a photocatalytic coating in a sample chamber, a source of reporter compound in fluid communication with the sample chamber, light sources that may activate the photocatalyst and excite the reporter compound, an optical detection unit capable of receiving a light signal from the second light source after it has passed through the sample chamber, and various pumps, valves or injection syringes that regulate the flow of sample and reporter compound into and out of the sample chamber.

Abstract: Methods and systems to determine a concentration of bromide ions in an aqueous sample are disclosed. The method involves the oxidation of bromide ions to bromine, followed by bromination of a colored or fluorescent reporter compound which may be detected by spectrophotometric means. The relative change in color or fluorescence upon bromine binding to the reporter compound may then be used to determine a quantitative concentration of bromide ions in the sample. The system utilizes a photocatalytic coating in a sample chamber, a source of reporter compound in fluid communication with the sample chamber, light sources that may activate the photocatalyst and excite the reporter compound, an optical detection unit capable of receiving a light signal from the second light source after it has passed through the sample chamber, and various pumps, valves or injection syringes that regulate the flow of sample and reporter compound into and out of the sample chamber.

Abstract: An electronic device of the type wherein a semiconductor stack is functionally supported by interconnects, electrical contacts and dielectric materials. The interconnects and electrical contacts are composed of iridium, ruthenium, zirconium, niobium, tantalum, rhodium, chromium, nickel, palladium, osmium, platinum, titanium, silver and their alloys. The dielectric materials are formed of mixtures of titanium oxide, zirconium oxide, iridium oxide, silver oxide, ruthenium oxide, and niobium oxide.

Abstract: Sensors for sensing/measuring one or more analytes in a chemical environment. Each sensor is based on a semiconductor structure having an interfacial region containing a two-dimensional electron gas (2DEG). A catalyst reactive to the analyte(s) is in contact with the semiconductor structure. Particles stripped from the analyte(s) by the catalyst passivate the surface of the semiconductor structure at the interface between the catalyst and the structure, thereby causing the charge density in the 2DEG proximate the catalyst to change. When this basic structure is incorporated into an electronic device, such as a high-electron-mobility transistor (HEMT) or a Schottky diode, the change in charge density manifests into a change in an electrical response of the device. For example, in an HEMT, the change in charge density manifests as a change in current through the transistor, and, in a Schottky diode, the change in charge density manifests as a change in capacitance.