Identification of tetrahedral amorphous carbon clusters on atomic hydrogen-etched graphite surface by scanning tunneling microscopy/spectroscopy

Scanning tunneling microscopy and spectroscopy have been used to study the electronic states of the islands located at the edges of hydrogen-etched graphite surface. Spectroscopy results have shown the presence of additional electronic states, energy gap, and lowering of the Fermi level. The obtained results are in accordance with the theoretical prediction for the presence of p-type tetrahedral amorphous carbon clusters (ta-C/ta-C:H) in perfect sp2 graphite network.