ZnO based gas sensor testing

This paper describes and presents an initial test result of ZnO based gas sensor applied to ethanol vapour detection. Intrinsic ZnO and Al (1 %) doped AZO thin films are deposited on SiO₂/Si substrate by spray pyrolysis method with in-situ optimised heater. X-ray diffraction analysis revealed that all the films are polycrystalline with c(002)-axis orientation wurtzite structure normal to the substrate surface. Test sensor detection was performed at operating temperature of 240°C for 100 ppm and 300 ppm of ethanol gas. A net resistance decreasing is obtained in response about three orders of magnitude.