Mapping electronic states of triple anti-parallel and symmetric zigzag grain boundaries of graphene on highly oriented pyrolytic graphite

Abstract

We studied the structures and electronic spectra of two periodic GBs in graphene on highly oriented pyrolytic graphite (HOPG) surface by using scanning tunneling microscopy and spectroscopy (STM/S). It was found that a GB consisting of triple anti-parallel dislocation arrays of pentagonal-heptagonal (5–7) carbon rings induced an enhanced localized state above the Dirac point, which was attributed to van Hove singularities (VHSs). The localized state was site dependent with the variation between 0.47 and 0.36 eV. Another periodic GB with a symmetric zigzag structure presented VHSs at −0.038 and 0.12 eV near the Fermi level. Moreover, intervalley scattering was observed on GBs. This finding further suggested that defect engineering might tune the electronic structures of graphene and even the performance of graphene-based electronic devices by properly mediating and designing ordered GBs in a graphene layer.