Novel aspects on the irradiation of HOPG surfaces with slow highly charged ions

As a continuation of our previous work, we present new results regarding the interaction of slow highly charged ions with HOPG. Lateral atomic force microscopy measurements with calibrated cantilevers were performed to investigate in more detail the locally enhanced friction at ion impact sites, which has been reported earlier. For very high charge states, apart from ever-present changes in frictional and electronic properties, we find evidence for true topographic surface modifications (hillocks). In complementary studies, we have investigated these structures regarding their conductivity by employing high-resolution conductive atomic force microscopy. In addition, we demonstrate the possibility to etch ion-induced surface structures by thermal annealing.