Graphene oxide incorporated ZnO nanostructures as a powerful ultraviolet composite detector

In this study, ultraviolet (UV) photodetection performance of graphene oxide (GO) incorporated ZnO composites with different contents of GO (0.25, 0.5, 1.0, and 2.0 wt%) is investigated. The presence of graphene oxide nanosheets in the composites is confirmed by microscopic images and spectroscopic tools. Scanning electron microscopy images showed a uniform distribution of GO nanosheets between ZnO nanostructures. Uniform dispersion of GO nanosheets between ZnO nanostructures was also approved by transmission electron microscopy. Based on X-ray diffraction spectra, it was found that GO nanosheets could be considered as seeds for inhomogeneous nucleation of ZnO nanoparticles. According to Raman spectroscopy, the number layers of graphene oxide nanosheets was calculated to be around 4-6. Finally, UV-detection measurements showed that 1.0 wt% of GO into ZnO nanopowder was accounted as optimal point. However, increasing the GO concentration gave rise to a substantial reduction in the responsivity of the samples. Indeed, we believe, in the sample whose GO concentration is more than 1.0 wt%, graphene sheets play as obstacles which decrease the amount of UV light absorbed by ZnO nanostructures.