Direct growth of ZnO nanowire arrays on UV-irradiated graphene

Abstract

In this study, we investigated the effect of UV irradiation of graphene on the hydrothermal growth of ZnO nanowires (NWs). We found that the density of ZnO NWs varied with respect to the UV irradiation time, with the highest density of ZnO NWs being achieved on a graphene surface that had been irradiated for 10 min. Transmission electron microscopy revealed that the ZnO NWs grew vertically on the graphene. The hydrophobicity of the graphene decreased after UV irradiation, enhancing the seeding and hydrothermal growth of ZnO NWs. Raman spectroscopic analysis revealed that UV irradiation of the graphene produced defects, which served as trapping centers during the seeding process. When UV irradiation was applied for more than 10 min, the number of carbon atoms with dangling bonds decreased, thereby decreasing the resulting density of ZnO NWs on the graphene. This facile strategy for growing uniform ZnO NWs on chemically inert graphene after UV irradiation should be suitable for adoption in other growth systems, potentially allowing the development of novel hybrid systems for use in electronic and optoelectronic devices.