Methane gas sensor application of cuprous oxide synthesized by thermal oxidation

Application of cuprous oxide (Cu2O) thin films for methane gas sensors was investigated. The Cu2O films were prepared by the thermal oxidation of Cu films under reduced partial pressure of oxygen. The XRD and AFM measurements were performed to investigate crystal structure and the surface properties of synthesized Cu2O films. According to the XRD patterns, the films had a preferred (111) orientation. Sensors were fabricated using synthesized Cu2O films and their sensitivity response times and recovery times were measured at different temperature for different methane concentrations. The sensor exhibited a high sensitivity, a fast response time and a fast recovery time for methane gas at an operation temperature low as 180 degrees C. The Cu2O has unique characteristics, such as has p-type conduction, high conductivity, and high carrier mobility. The fast and high response of Cu2O sensor for methane was explained as due to the increase of resistance in intrinsic p-type Cu2O in the presence of methane gas. (C) 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim