Investigation of Pt/Ga2O3-ZnO/SiC Schottky diode based hydrocarbon gas sensors

Silicon carbide based metal-oxide-semiconductor (MOS) devices are attractive for gas sensing in harsh, high temperature environments. We present a novel hydrocarbon gas sensor based on a catalytic Metal-Reactive Insulator-Silicon Carbide (MRISiC) device. This sensor has been employed as a Schottky diode. The sensor presented is capable of operating at temperatures around 600 °C. It has been exposed to propene gas, which lowers the barrier height of the diode. The MRISiC devices are based on semiconducting Ga2O3 - ZnO thin films prepared by the sol-gel process. The thin films were deposited onto the SiC by the spin coating technique and a Pt layer was deposited on the top of the metal oxide layer forming the Schottky barrier. The sensors responses were stable and repeatable towards propene at operating temperatures between 300 and 600 °C. In this paper the effect of biasing is investigated by analyzing the output voltage of the diodes when biased at constant currents of 2 and 8 mA.