Effect of variable thickness on liquefied petroleum gas sensing response of ZnO thin films

Abstract

In the present study, transparent and crack free ZnO thin films were casted on silicon substrate by using spin coating technique to analyze the effect of variable thickness. The crystallographic structure of as-prepared thin films were characterized using X-ray diffraction (XRD) technique and it was revealed that all the compositions exhibit hexagonal wurtzite-type crystal symmetry with P63mc. Surface morphology and granular microstructure illustrated uniform distribution and well-interlinking of grains and film thickness of ZnO@1, ZnO@2, and ZnO@3 samples was found to be 80 nm, 155 nm, and 230 nm, respectively. The effect of liquefied petroleum gas (LPG) purging on varying thickness of ZnO thin films were carried out lab customized gas calibrated testing apparatus. The sensing response increased significantly from to 225% with an optimal thickness of 155 nm and an operating temperature of 180 °C.