Experimental evidence of a single nano-graphene

A single nano-sized graphene sheet is prepared by a combination of electrophoretic deposition (EPD) and heat-treatment of diamond nano-particles on a highly oriented pyrolytic graphite (HOPG) substrate. Heat-treatment at 1600 °C converts diamond nano-particles to single nano-graphenes, where the mean in-plane size and the inter-layer distance from the substrate are estimated at 10–15 and 0.35–0.37 nm, respectively. The considerably large inter-layer distance compared to bulk graphite suggests a large reduction of inter-layer interaction, although a nano-graphene is placed epitaxially on the substrate. The isolated single nano-graphene provides an important model of nano-sized π-electron system, for which recent theory predicts unconventional electronic structure of edge-inherited non-bonding state.