Local conductance measurement of few-layer graphene on SiC substrate using an integrated nanogap probe

Abstract

We report the first measurement of spatially resolved in-plane conductance of few-layer (one- or two-layer) graphene grown on a SiC substrate, measured using an integrated nanogap probe. The morphology and number of layers of the thermally grown graphene were confirmed by in-situ observation using low energy electron microscopy (LEEM). The gap current (conductance) images were measured using an integrated nanogap probe with a 30-nm-gap on a conventional SPM system in vacuum. Island shapes with a typical width of 30 nm were clearly observed in the conductance image. Single- and double-layer graphene islands could be clearly distinguished, because the conductance of double-layer graphene is about four times that of single-layer graphene. The layer number of few-layer graphene has been successfully estimated from the electrical transport measurement using the integrated nanogap probe.