STM Studies of Graphene Films Prepared by Sonication-Assisted Dispersion

We present STM (Scanning Tunneling Microscopy) studies of thin graphene films prepared by a spraying technique via direct~exfoliation of graphite in organic solvent (dimethylformamide). Our results show that these films are a patchwork of an unperturbed hexagonal graphene network mixed with heavily functionalized areas. The area of graphene-like spots does not exceed 10nm$^{2}$. Further, we discuss the influence of chemical reduction of these films on their atomic structure.