Measuring the implantation depth of silver clusters in graphite

Scanning tunnelling microscopy (STM) and molecular dynamics (MD) simulation s have been used to investigate the implantation of Ag-7(-) clusters into t he graphite surface. An experimental measure of the implantation depth of i ndividual clusters is gained via thermal oxidation of the bombarded graphit e surfaces. This process results in etching of the cluster-induced defects to form etch pits which grow laterally whilst retaining the depth of the im planted cluster. STM imaging of the etch pits reveals the distribution of i mplantation depths for deposition energies of 2 keV and 5 keV. Molecular dy namics simulations for clusters of 5 keV energy show that the implantation depth for Ag-7(-) is largely independent of the impact site on the graphite surface and the cluster orientation. The implantation depth found by MD li es at the upper edge of the experimental depth distribution.