Characterization of Ga2O3 based MRISiC hydrogen gas sensors

This paper presents the results of our investigations on the hydrogen gas response of Pt/Ga2O3/SiC devices operated as Schottky diodes highlighting the importance of gallium oxide as a layer within the device. The Ga2O3 thin films were prepared using the sol-gel technique. The investigation reported in this paper also includes the compositional characterization of the Ga2O3 films using X-ray photoelectron spectroscopy (XPS) and Rutherford backscattering spectroscopy (RBS). Results show the films consisted of stoichiometric Ga2O3, with a thickness of less than 100 nm. RBS analysis indicated that the films are stoichiometric and reproducible. For gas sensing experiments, the diodes were biased at a constant current varying between 1 and 2 mA and their responses to H-2 in different ambient was measured. The sensors were extremely stable, varying from its mean baseline value by only 0.014%. When operated in oxygen rich ambient the magnitude of the responses was larger. The response and recovery times also appear to be large, owing to nearly total interaction or combustion of the dissociated hydrogen molecules on the surface of the device. (C) 2004 Elsevier B.V. All rights reserved.