ß-Ga2O3 flake based Schottky diode hydrogen sensor

2D (2-dimensional) (100) plane β phase Ga2O3 (β-Ga2O3) flake based Pt Schottky diode is demonstrated for hydrogen sensing application. The (100) plane β-Ga2O3 flake was formed from the side wall of a mother (2̅01) plane β-Ga2O3 bulk substrate by the cost-effective mechanical exfoliation method. The hydrogen response of the (100) plane Ga2O3 flake based diode with the catalytic Pt Schottky electrode for hydrogen decomposition reaction was measured in the wide concentration range of 50–40,000 ppm hydrogen. The β-Ga2O3 flake based hydrogen sensor showed excellent responsivity of 2.32 × 108% for the 500 ppm hydrogen exposure at 25°C, and exhibited a reliable hydrogen sensing behavior up to 400°C. The decent cross-selectivity of the (100) plane β-Ga2O3 flake based Pt Schottky diode sensor over the other gases including N2, CO, CO2, CH4, NO2, NH3, and O2 was observed. In addition, the effect of the humidity on hydrogen sensing was investigated.