Implantation of size-selected silver clusters into graphite - Linearity of implantation depth vs. scaled momentum

We report on a systematic study of the implantation of size-selected Ag-N(+) sample, for different cluster sizes (N = 1 3, 7, 9 13) and different impact energies (E = 1-30 keV). Results show that the implantation depth scales linearly with the momentum of the cluster, with a stopping power which depends on cluster size. We have particularly investigated the effects of the size and the geometry of the cluster on the implantation into the graphite substrate. A sort of universal behavior, which unifies different elements and different cluster geometries, can be recognized by scaling the momentum with the cluster projected surface. The stopping power of the cluster while penetrating the HOPG surface has been investigated for each cluster size, and a molecular effect is recognized, meaning that the stopping power is not additive in the number of atoms of the cluster.