CO and NO2 sensing properties of doped-Fe2O3 thin films prepared by LPD

The CO and NO2 sensing properties of iron oxide thin films doped with Au and Zn and prepared by a liquid-phase deposition method (LPD) have been investigated. The undoped Fe2O3 sensor was found to be sensitive to NO2 but not to CO. The addition of Zn increases the sensitivity at low temperature towards NO2 and decreases strongly the intrinsic resistance of the iron oxide film. The addition of gold was necessary to obtain a detectable response to CO, the Au-doped ZnO sensor was found the most sensitive to CO. By operating at an appropriate temperature, these sensors could be able to detect selectively CO and NO2, with negligible humidity cross-sensitivity.