  Raman imaging on the edges of single layer micromechanical cleavage graphene
(MCG) was carried out. The intensity of disorder-induced Raman feature (D band
at ~1350 cm-1) was found to be correlated to the edge chirality: it is stronger
at the armchair edge and weaker at the zigzag edge. This shows that Raman
spectroscopy is a reliable and practical method to identify the chirality of
graphene edge and to help in determination of the crystal orientation. The
determination of graphene chirality is critically important for fundamental
study as well as for applications.
