Study of Ga2O3 thin film gas sensors

In this paper we present the gas sensing performance of pure, doped and Pt modified Ga₂O₃ thin films prepared by the sold-gel process. The oxygen gas sensing performance of the binary compound Ga₂O₃ is compared with that of pure Ga₂O₃ and ZnO. The Ga₂O₃-ZnO binary compound sensor showed preferred gas sensing in the temperature range of 450 to 550°C and outperformed the pure Ga₂O₃ and ZnO sensors for every oxygen gas concentration tested. Furthermore, the stoichiometry of the semiconducting Ga₂O₃ has been confirmed by X-ray photoelectron spectroscopy (XPS). For H₂ measurements, a 70nm layer of Pt was deposited on top of the Ga₂O₃ to enhance the response and a comparison of the device with and without this layer is also presented. It was found that the addition of the Pt layer decreased the H₂ response and recovery times by over 65%.