O2 sensing properties of Zn- and Au-doped Fe2O3 thin films

Zn- and Au-doped iron oxide thin films have been prepared by liquid phase deposition. These films have been characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Their performance as oxygen gas sensors has been measured. It has been shown that both the Zn and Au dopants increase the oxygen response of the pure iron oxide films. The XRD and SEM results show that Zn changes both the microstructure and the particles size of the sensing layer through the formation of a solid solution with iron oxide. However, the strong increase in sensitivity to oxygen of the Au-doped Fe₂O₃ film has been related to the more favorable chemisorption of oxygen on the small gold particles at the interface with the semiconductor oxide. The results show that Au-doped iron oxide sensors are most promising for oxygen gas sensing.