Modification of highly oriented pyrolytic graphite (HOPG) surfaces with highly charged ion (HCI) irradiation

Slow Ar8+ irradiation and the following electron injection creates a non-conductive area to a depth of a few nanometers on a highly oriented pyrolytic graphite surface (HOPG). The annealing of the sample in a hydrogen atmosphere stabilizes the Ar8+ impact area, which results in the field emission from the impact region. The property of the field emission is similar to that of diamond-like carbon (DLC), suggesting the possibility that sp(3) hybridization occurs at the Ar8+ impact region. The work function estimated from the Fowler-Nordheim plot is much lower than nontreated HOPG and similar to a hydrogen-terminated DLC film. (C) 2003 Published by Elsevier Science B.V.