Vacuum-ultraviolet photoreduction of graphene oxide: Electrical conductivity of entirely reduced single sheets and reduced micro line patterns

Abstract

We here report a scanning probe method to locally and directly research the electrical properties of vacuum-ultraviolet (VUV) reduced graphene oxide. The measured electrical conductivity of individual VUV-reduced GO (VUV-rGO) sheets by using conductive atomic force microscopy (CAFM) reached 0.20 S·m[−1] after 64 min irradiation, which was clearly enhanced compared with the pristine GO. According to the X-ray photoelectron spectroscopy results, the recovered conductivity of VUV-rGO could be ascribed to the partial elimination of oxygen-containing functional groups and the rapid reconstruction of the C=C bonds. Heterogeneously distributed low- and high-conductivity domains (with a diameter of tens of nanometer to ca. 500 nm) were found from current mapping of the VUV-rGO sheet. By applying photomask lithography, rGO regions were drawn into single GO sheet and were researched by CAFM. The in-plane lateral conductivity of rGO regions increased obviously compared with pristine GO regions.