High Sensitivity Hydrogen Sensors Based On Gan

High quality graphite based Schottky diodes are presented. Schottky barriers were prepared by mechanical deposition of colloidal graphite on GaN substrates uncoverd and partly covered with Pt nanoparticles deposited by electrophoretic techniques. The electron transport for both diodes can be well described by thermionic emission. Hydrogen sensing characteristics of graphite-Pt/GaN Schottky diodes were investigated. Temperature dependence of the sensitivity, the barrier height variation, the ideality factor and the barrier height itself were studied. The proposed hydrogen sensor responds well to various hydrogen containing gases. The room-temperature sensitivity response of 2x10(7) was obtained in 1000 ppm H-2/N-2 ambient. (C) 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim