LAUSR

Abstract This article reveals the gas-sensitive properties of polycrystalline gallium oxide thin films with chromium additives. Incorporation of the Cr2O3 phase into the β-phase gallium oxide film structure leads to the Ga2O3 grain size decrease. The oxygen-sensitivity of the gallium oxide films appears at 300 °C. The oxygen increases reversibly the sensor resistance due to an increase in the height of the energy band bending at the Ga2O3 grain boundary with the chemisorption of atomic O−. The chromium oxide formed in the Ga2O3 films stimulated dissociative adsorption of the oxygen due to its high catalytic activity via a spill-over mechanism. The temperature range of 500–700 °C appears to be the most efficient for the oxygen detection in the concentration range from 9 to 100 vol%. The response time of the sensor was 20 s at 700 °C in an initial nitrogen-containing atmosphere at О2 exposure to 21 vol% and the recovery time comprised 52 s. Meantime, the sensors did not practically react to a gas reducing and high humidity.