Hydrogen Sensing Characteristics of Pt Schottky Diodes on ((2)over-bar01) and (010) Ga2O3 Single Crystals

Abstract

We investigated the hydrogen sensing characteristics of Pt Schottky diodes on ((2) over bar 01) and (010) beta-Ga2O3 bulk crystals. The Pt Schottky diodes on beta-Ga2O3 wafer exhibited the fast, reversible, and cyclic response upon hydrogen exposure. The maximum value of the relative current change of the ((2) over bar 01) Ga2O3 diode sensor was as high as 7.86 x 10(7) (%) at 0.8 V, which is slightly higher than that of the (010) Ga2O3 diode. The hydrogen responses of both beta-Ga2O3 diode sensors are believed to result from oxygen and gallium atomic configurations of Ga2O3 surfaces for hydrogen adsorption. The Pt Schottky diodes of Ga2O3 wafers did not show any clear response to other gases, such as N-2, CO, CO2, O-2, CH4, NO2, and NH3. Our finding suggests that the Pt Schottky diodes on beta-Ga2O3 hold great potential for the applications of hydrogen gas sensors with high sensitivity and selectivity. (C) The Author(s) 2018. Published by ECS.