Effect of thickness on structural and acetone gas sensing properties of graphene oxide/zinc oxide thin films

Graphene oxide (GO) and zinc oxide (ZnO) are promising materials for gas sensing applications due to their unique properties. This study investigates the effect of thickness on the structural and acetone gas sensing properties of graphene oxide/zinc oxide (GO/ZnO) thin films. The thin films were fabricated on a glass substrate using the spin coating technique, varying thicknesses from 90 to 220 nm. By increasing the number of deposited layers, the thickness of the thin films was altered. 2-Methoxyethanol, an effective solvent, disperses GO to form a stable solution for spin coating. X-ray diffraction (XRD) was used to analyze the structural characteristics of the GO/ZnO thin films, showing an increase in the average crystallite size with an increase in the number of deposited layers. Field Emission Scanning Electron Microscopy (FESEM) examined the surface morphology of the prepared thin films, and the results show that spherical nanoparticles with a size of 28 nm have formed. Two primary peaks can be seen in the visible region of photoluminescence spectra: a blue emission peak with a center at 465 nm and a green luminescence peak with a centre at 557 nm. The chemo-resistive method was used to examine the gas sensing capabilities by subjecting the prepared samples to different concentrations of acetone gas at room temperature. Maximum response of 22.63% and a short response time of 65 s at 200 ppm are achieved by the GO/ZnO thin film with six layers of deposition.