Implantation of size-selected Si clusters into graphite

Molecular dynamics simulations have been performed to explore the implantation of silicon clusters into a graphite substrate to well-defined depths. The cluster sizes range from N=20 up to N=200 atoms per cluster, deposited with kinetic energies from E=500 eV up to E=5000 eV per cluster. We find that the clusters remain intact as coherent, amorphous structures after implantation. The implantation depth is well defined and scales with the kinetic energy of the clusters and the inverse of the cross-sectional area. This indicates a constant decelerating force, associated with the lateral displacement of carbon atoms as the cluster “drills a hole” in the substrate. The main dissipation channels for the energetic silicon clusters are the creation of phonons in the graphite substrate and the breaking of C–C bonds.