SENSING REDUCING GASES AT HIGH-TEMPERATURES USING LONG-TERM STABLE GA2O3 THIN-FILMS

Polycrystalline semiconducting Ga2O3 thin films represent a promising new basic material for sensors used to detect reducing gases at operating temperatures up to 650-degrees-C. The electrical conductance of the Ga2O3 films provides the sensor signal. Fundamental investigations with two-component gas mixtures of a reducing gas in an inert gas are reported. The results show a long-term stable dependency of the conductance of the Ga2O3 thin films on the partial pressure of the reducing gas according to G approximately p(r.g.)1/3 at constant sensor temperature for the case of H-2 and CO. In contrast to other metal oxides, Ga2O3 exhibits no disturbing bulk O2 sensitivity below 700-degrees-C.