Characterization of CVD-synthesized graphene films transferred on different substrates using the scanning probe microscopy electrical techniques

Abstract

The use of local electrical characteristics of graphene films prepared by chemical vapor deposition (CVD) method on Cu and transferred on different substrates such as glass, SiO 2 /Si and Al 2 O 3 substrates was discussed. The topography, Kelvin probe force microscopy (KPFM), scanning capacitance microscopy (SCM) and electrostatic force microscopy (EFM) were compared for graphene on the three different dielectric substrates. The surface potentials of graphene films were investigated using KPFM. It was found that graphene films exhibited nonuniform surface potential distribution depending on the sort of the underlying substrate used, the number of graphene layers and the presence of graphene film defects such as edges, wrinkles etc. The EFM results demonstrated that the local electrostatic properties of graphene film on Al 2 O 3 substrate differ significantly compared to that on glass and SiO 2 /Si substrates. The cross-correlation coefficients between topographical image and SCM- and EFM-images were estimated in order to compare these techniques. It was shown that the techniques can bring complementary information for the characterization of graphene films on different substrates relevant for applications. • The local electrical properties of graphene films were investigated by KPFM, SCM and EFM techniques. • The quantitative values of local dielectric properties are sensitive to the underlying substrate. • Kelvin probe force microscopy. • Scanning capacitance microscopy. • Electrostatic force microscopy.