Development of a room temperature thin film In2O3, ZnO and SnO2 ozone sensor

Thin films of Indium-zinc-tin oxide have been prepared by Vacuum Thermal Evaporation (VTE). The sensing characteristics of these films to environmentally relevant ozone concentrations were studied at room temperature. The effects of film thickness, deposition rate and annealing were investigated. The resistance of the thin film was found to be inversely proportional to the deposition rate. The highest sensitivity of the ozone sensors was found at a deposition rate of 1.2 nm/s - 1.4 nm/s. In addition the O₃ sensors were found to perform best with a 40 nm thick sensing layer. ln₂O₃, ZnO and SnO₂ were deposited on alumina substrates containing interdigitated electrodes by means of VTE. These results have shown that In₂O₃:ZnO:SnO₂ thin films prepared by VTE method are promising for room temperature ozone sensing.