Gas sensitivity of PECVD β-Ga2O3 films with large active surface

Abstract

The gas-sensitive properties of Ga2O3 films, first synthesized by plasma-enhanced chemical vapor deposition (PECVD), with respect to gaseous species of environmental and industrial interest were investigated in detail. The addition of some N2 during the PECVD process made it possible to reduce the inherent high resistance of Ga2O3 material and increase its gas sensitivity. The PECVD-Ga2O3 films demonstrated high responses to H2, O2 and NH3 with maximum response temperatures of 600 °C, 700 °C and 350 °C, correspondingly. The responses of Ga2O3 films to 1 vol % of H2, 40 vol % of O2 and 1 vol % of NH3 at these temperatures were 400.73 %, 480.22 % and 335.35 %, correspondingly. The short response and recovery times of 7.6 s and 31.0 s have been achieved under H2 exposure. A plausible mechanism of the sensory effect of the PECVD-Ga2O3 films was suggested. Thus, the PECVD synthesized Ga2O3 films demonstrate a large potential for the development of high-speed performance H2 and O2 sensors working at high temperatures.