IGZO-decorated ZnO thin films and their application for gas sensing

In this study, indium–gallium–zinc oxide (IGZO)-decorated ZnO thin films were investigated through the change in IGZO deposition time for the detection of NO2 gas. The atomic layer deposited ZnO on interdigitated Au electrode alumina substrates are decorated with IGZO by controlling the deposition time. The IGZO (ZnO:Ga2O3:In2O3 = 1:1:1 mol. %) polycrystalline target was used for deposition and effect of deposition time was investigated. The sensor responses (Rgas/Rair) of 20.6, 39.3, and 57.1 and 45.2, 102.5, and 243.5 were obtained at 150 °C, 200 °C, and 250 °C and 25-ppm NO2 concentration for ZnO (Z1) and IGZO-decorated ZnO (Z3) films, respectively. The sensor response (Rgas/Rair) increased from ∼27 to 243.5 by decorating the ZnO film with IGZO for a 60-s sputtering time. The sensor recovery and response times of the IGZO-decorated ZnO/ZnO sensor increased, and the sensor selectivity to different gases was also evaluated.