Fabrication of Zinc Oxide Thin Film Sensor for Carbon Monoxide Gas Detection by Ultrasonic Spray Pyrolysis

Here, we have reported the thin film preparation of undoped zinc oxide thin films by ultrasonic spray pyrolysis and their gas response characteristics of carbon monoxide (CO). Four thin films of zinc oxide (ZnO) were deposited on glass substrates using a starting solution prepared from a ball milled precursor. A 0.2 M of zinc precursor (zinc acetylacetonate) was grinded using ball milling for different durations (15, 30, 45, and 60 min) and its effect was studied on gas sensing characteristics along with structural and morphological. Structural properties indicated that all the undoped ZnO thin films were grown with (002) plane orientation irrespective of milling conditions. Surface morphologies acquired from scanning electron microscopy revealed that milling time influenced in modifying the morphology. The films were formed with different types of hexagonal structures such as irregular, broken, twisted, and trigonal tipped hexagonals. Additionally, gas response measurements showed that films prepared using less milling time exhibited highest CO gas response, among other films.