Investigation of the nanoscale features fabricated on the HOPG surface induced by STM electric lithography under different voltage regions in ambient conditions

Carbon-based materials have attracted more and more interests in the nanotechnology and high attention has been paid to their fabrication and application. In this work, the nanofabrication of the highly oriented pyrolytic graphite (HOPG) surface was carried out by means of STM direct lithography under voltage pulse. Distinct characteristics of the fabricated features were obtained under different voltage magnitudes. Specifically, we observed the phenomena of exfoliation and folding of the graphite flakes on the HOPG surface above 5 V or so. Detailed study of the process parameters, such as the feedback, the driving of the sample platform, the current value was also performed. Moreover, the segmented current density of the tunnel junction was calculated from J.G. Simmonsʹs equations. Local anodic oxidation and nano explosive damage caused by the electrical breakdown of dielectric gap were put forward as the possible mechanisms to explain the fabricated results.