  Single layer graphene islands with a typical diameter of several nanometers
were grown on a Pt (111) substrate. Scanning tunneling microscopy (STM)
analysis showed most of islands are hexagonally shaped and the zigzag-type edge
predominates over the armchair-type edge. The apparent height at the atoms on
the zigzag edge is enhanced with respect to the inside atoms for a small sample
bias voltage, while such an enhancement was not observed at the atoms on the
armchair edge. This result provides an experimental evidence of spatially (at
the zigzag edge) and energetically (at the Fermi level) localized edge state in
the nanographene islands, which were prepared chemically on Pt (111).
