Hydrogen sensors based on Pt/α-Ga2O3:Sn/Pt structures

Gas sensing properties of Schottky metal-semiconductor-metal (MSM) structures based on α-Ga2O3 epitaxial films with Pt contacts are investigated. The electrical conductivity of the MSM structures exposed to H2, O2, CO, NO, CH4 and NH3 gases in the temperature range of 25–500 °C is studied. The structures show a very high sensitivity to H2. It is found that Pt contacts and the Sn doping level play a key role in determining the hydrogen sensing properties of Pt/α-Ga2O3:Sn/Pt MSM structures. The sensitivity to H2 is attributed to a modulation of the Schottky barrier height at the interface between Pt and α-Ga2O3:Sn.