Localized electronic structures of graphene oxide studied using scanning tunneling microscopy and spectroscopy.

We have used scanning tunneling microscopy (STM) to elucidate the nanoscale electronic structures of graphene oxide (GO). The unreduced GO layer was imaged using STM without reduction processes when deposited on a Au(111) surface covered with an octanethiolate self-assembled monolayer (C8S-SAM). The STM image of the GO sheet exhibits a grainy structure having a thickness of about 1 nm, which is in good agreement with the previous results obtained using atomic force microscopy (AFM).