Atomic-scale Study of Scattering and Electronic Properties of CVD Graphene Grain Boundaries

Chemical vapor deposition growth of graphene on polycrystalline copper foil is a demonstrated technique for obtaining large-area, predominantly monolayer graphene. However, such growth results in grain boundaries between rotationally misoriented graphene grains. We employ scanning tunneling microscopy and spectroscopy to examine the electronic properties of grain boundaries (GBs) and scattering off them in polycrystalline graphene grown by chemical vapor deposition on Cu foil and transferred to SiO2 substrates. Spectroscopy shows enhanced empty states tunneling conductance for most of the GBs and a shift towards more n-type doping compared to the bulk of the graphene. Fourier analysis of the electronic superstructure patterns adjacent to GBs indicates that backscattering and intervalley scattering are the dominant mechanisms, leading to the mobility reduction in the presence of GBs in CVD-grown graphene.