  Graphene is attracting vast interest due to its superior electronic and
mechanical properties. However, structure and electronic properties of its edge
are often neglected, although they are important for nanoscale devices because
the edge ratio becomes larger by decreasing the device size. In this study, we
suggest a way to fabricate a graphene with atomically aligned zigzag edges by
applying hydrogen-plasma etching (HPE) technique. By patterning a graphene
prior to HPE, it is succeeded to shape a graphene in desired structure. Both
atomic force microscopy and Raman spectroscopy confirm that the graphene shaped
by this technique preserves its honeycomb structure even on the edge, which is
aligned with zigzag structure. Although the mechanism of the anisotropic
etching by hydrogen-plasma have not been clarified yet, the sample position
dependence of the etching rate suggests that the hydrogen-radicals are
responsible for the anisotropic etching.
