High temperature hydrocarbon sensing with Pt-thin Ga2O3-SiC diodes

Silicon carbide based metal-oxide-semiconductor (MOS) devices are attractive for gas sensing in harsh, high temperature environments. We present a hydrocarbon gas sensor based on a Pt-thin Ga2O3-SiC device. This sensor has been employed as a Schottky diode, and is capable of operating at temperatures around 600° C. Exposure to propene (C3H6) gas results in shift towards lower voltages in the current-voltage (I-V) characteristic curve, as well as a change in series resistance of the diode. The Ga2O3 thin films were prepared by the sol-gel process and deposited onto the SiC by spin coating. The Pt layer was deposited on the top of the Ga2O3, forming the Schottky contact. It also serves to dehydrogenate the hydrocarbons. 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 different constant currents.