Abstract

Local photodegradation of graphene oxide sheets at the tip of ZnO nanorods was used to achieve semiconducting graphene nanomeshes. The chemically exfoliated graphene oxide sheets, with a thickness of approximately 0.9 nm, were deposited on quartz substrates. Vertically aligned ZnO nanorod arrays with diameters of 140 nm and lengths of <1 microm were grown on a glass substrate by using a hydrothermal method. The graphene oxide sheets were physically attached to the tip of the ZnO nanorods by assembling the sheets on the nanorods. UV-assisted photodegradation of the graphene oxide sheets (with dimension of approximately 5x5 microm) at a contact place with the ZnO nanorods resulted in graphene nanomeshes with a pore size of approximately 200 nm. The graphene nanomeshes prepared by using the photocatalytic property of the ZnO nanorods contained smaller oxygen-containing carbonaceous bonds and higher defects as compared to the as-prepared graphene oxide sheets. When chemical reduction of the graphene nanomeshes by hydrazine was used, the oxygen bonds of the nanomeshes more decreased while their graphitization increased. Based on X-ray photoelectron spectroscopy at low binding energies, the graphene nanomeshes reduced by hydrazine exhibited as a broad sheet a p-type semiconductor with an approximately 1.2 eV energy gap between the valence band and the Fermi level.