Scanning transmission electron microscopy studies of the deposition of size-selected sub-nanometre platinum clusters

Size-selected cluster ions containing four atoms of platinum (Pt-4(-)) have been deposited onto graphite at different deposition energies and investigated by high angle annular dark field imaging in a scanning transmission electron microscope. Pt-4 clusters deposited at 50 eV were observed to diffuse and aggreaate on the surface, while Pt-4 clusters deposited at 1 keV were found to be implanted and immobilised. An intermediate regime of deposition energy, in which only a fraction of the incident clusters are implanted, was also identified.