Pinning and implantation of size-selected metal clusters: a topical review

This paper presents a topical review of the deposition of size-selected metal clusters, specifically Ag-N(+), on graphite, which has been explored via a combination of molecular dynamics (MD) simulations and scanning tunnelling microscopy (STM) experiments. The size-selected metal clusters were fabricated by a magnetron sputtering, gas aggregation cluster beam source. It has been shown that the clusters are pinned to the surface when the impact energy exceeds a critical value, which is proportional to the cluster size. At very high cluster impact energies, the clusters penetrate the graphite surface and become implanted. For medium size clusters (N = 20-200 atoms), it was found via the MD simulations that the implantation depth varies linearly with the impact energy and cluster size as Dsimilar toE/N-2/3. For small clusters, e.g. Ag-7(+), both MD simulations and experiment revealed a linear dependence of the implantation depth on cluster velocity rather than cluster impact energy. (C) 2002 Elsevier Science Ltd. All rights reserved