Creation of nanodiamonds by single impacts of highly charged ions upon graphite

The local modification of the electronic states of highly oriented pyrolyti c graphite (HOPG) surfaces using highly charged ion (HCI) irradiation has b een demonstrated as a promising technique in the design of nanoscale materi als. The high potential energy of HCI and subsequent surface treatment by e ither electron injection from a scanning tunneling microscopy (STM) tip or by He-Cd laser irradiation provide a localized transition from sp(2) to sp( 3) hybridization in HOPG, resulting in the formation of nanoscale diamond-l ike structures (nanodiamond). It is of interest that a single impact of HCI creates one nanodiamond structure without inducing any defects in the area surrounding the impact region, suggesting potential applications of HCI in nanoscale material processing. (C) 2001 American Institute of Physics.