Ultrasonically prepared nanocrystalline ZnO thin films for highly sensitive LPG sensing

Nanocrystalline ZnO thin films were prepared by ultrasonically spraying zinc acetate onto the heated glass substrate. The films were fired at 500 °C. As prepared thin films were studied using XRD, AFM, TEM and EDAX to know crystal structure, size of crystallites, surface morphology, microtopography and elemental composition respectively. The ZnO films were found to be of hexagonal in crystal structure and nanocrystalline in grain size. The gas sensing performance of the ZnO thin films, sprayed for different intervals of time, was studied on exposure of various gases. The films were observed to be most sensitive (S = 1727) to LPG at 300 °C. Furthermore, the LPG sensor reported is cost-effective, user friendly and easy to fabricate.