The effect of graphene and cobalt on ethanol sensing performance of ZnO based sensor prepared by sol-gel method

Abstract The sol-gel method was used to synthesize pure zinc oxide, graphene doped zinc oxide, cobalt doped zinc oxide and graphene/cobalt doped zinc oxide samples to investigate their sensing properties. Different physical properties of the samples have been investigated and compared through X-ray diffraction (XRD), field emission scanning electron microscopy and Fourier transform infrared spectroscopy. Using the XRD results, the lattice parameter increased with doping of the samples. Based on the analyses, the formation of zinc oxide in all samples and the related signs of graphene and cobalt were approved. With the aid of an electric circuit, all of the samples were exposed to different concentrations of ethanol. The best response/recovery time was reported for all samples at 3000 ppm. Doping of the samples had a significant effect on reducing the response/recovery time and increasing the sensitivity, which is a significant case for semiconductor gas sensors.