Local current mapping of electrochemically-exfoliated graphene oxide by conductive AFM

Electrochemical exfoliation of graphite is one of the promising methods for the mass-production of graphene oxide (GO). The analysis of chemical condition, structure, and the electrical property of graphene-like materials, which is usually evaluated by X-ray photoelectron spectroscopy or micro Raman spectroscopy, is important for the practical application. However, the information obtained by these instruments are spatially averaged. In this report, electrical property of mono-layer electrochemically-exfoliated GO (EGO) sheet was directly measured by conductive atomic force microscopy (C-AFM). Although there was little difference between EGO and GO synthesized by conventional chemical oxidation routes (CGO) in terms of chemical and structural characteristics, the electrical conductivity of EGO was much higher (27 000 S m(-1)) than that of CGO which is considered as the insulating material. These results proved the significance of C-AFM for unveiling the relationship between the structure and the electrical properties of graphene-like materials. (C) 2020 The Japan Society of Applied Physics.