Tailoring graphite layers by scanning tunneling microscopy

We have investigated the tailoring of graphite layers using a scanning tunneling microscope (STM). Water-adsorbed graphite surfaces were tailored at ambient temperature and atmospheric pressure by oxidizing the surface carbon atoms under a high bias voltage between an STM tip and the surface. We thereby tailored the graphite surface from one to several layers in depth. We observed that graphite surface fabrication using an STM occurred above a threshold bias voltage, and found that the threshold voltage depended on the STM tip scanning speed. By optimizing the bias voltage and the tip scanning speed, we obtained graphite nanostructures within a square of about 30 nm minimum length. The STM tailoring could also be successfully applied to carbon nanotubes, scratching and slicing them. These results indicate that the STM can be used to tailor graphene sheets producing well-defined graphite nanostructures. (C) 2003 Elsevier B.V. All rights reserved.