A selective, temperature compensated O2 sensor based on Ga2O3 thin films

Pure semiconducting Ga2O3 thin films show a reaction to reducing gases as well to oxygen variations at operation temperatures between 600 degrees C-900 degrees C. By applying surface modifications with catalytically active oxides like La2O3 or CeO2, a complete suppression of the reaction to reducing gases in oxygen-rich atmospheres could be achieved, yielding devices that only respond to the oxygen content. By an analysis of the desorbing gases with NIR-Spectroscopy, varying production rates of carbon oxides and unsaturated carbohydrates were observed. A modification with manganese oxide yielded complete gas-insensitive devices, which still show a thermal-activated conductivity. This effect can he used for temperature compensation purposes. (C) 2000 Elsevier Science S.A. All rights resented.