Effect of Au Doping on ZnO Nanoporous Structure for H2S Gas Sensing

Abstract

This research mainly constitutes the fabrication of semiconductor gas sensors using high Power pulse magnetron sputtering (HiPIMS) technology to deposit ZnO thin films. As a doping substance, different thicknesses of gold plating is deposited on the surface of ZnO thin films. Various thicknesses of gold used in the study are 3.3 nm, 6.6 nm, 10 nm, 13.3 nm and 16.6 nm. The structural properties of thin films were identified by X-ray- diffraction (XRD), scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDS). EDS analysis conveyed that gold particles filled the pores of nanoporous ZnO structures, which increased the films surface area and enhancing the gas sensing response. Various concentrations of H2S gas is used to test the gas sensing properties and the results proved the Au doped ZnO thin film sensor has enhanced sensing than the pure ZnO thin film sensor. 10 nm thickness doped Au has prime sensing properties with the operating temperature of 300 °C. Other sensing properties such as repeatability, selectivity and effect of humidity are tested and presented the data which shows the Au doping ZnO superiority over pure ZnO thin films.