Field ion microscopy images of multilayered graphene and graphene oxide

Abstract

Field emission and field ion microscopy (FIM) of graphene edges exhibit exotic images with enigmatic fine structures, which are not expected in ordinary metal emitters such as tungsten and molybdenum. Graphene emitters were prepared by three methods; scratching highly oriented pyrolytic graphite by a tungsten needle, electrophoretic deposition of graphene oxide (GO), and putting droplets of GO solution on the tip of a tungsten needle. FIM of graphene show arrayed sharp streaks, split-double spots, and hollow “race-track” shaped spots, running transverse to a graphene plane. It is speculated that these patterns originate from vacant electronic states and reflect the symmetry and distribution of π*-orbitals at graphene edges.