Surface nanostructures created by cluster-surface impact

Abstract

This paper presents a review of the production of surface nanostructures from the controlled deposition of size-selected clusters on graphite. At high enough impact energies, the clusters can be implanted into the graphite surface to create open ‘well’ structures. Scanning tunnelling microscopy (STM) measurements, coupled with molecular dynamics (MD) simulations, for Au 7 +, Ag 7 + and Si 7 + clusters exhibit scaling relations which reveal that the implantation depth scales linearly with the momentum of the clusters in all cases. At lower impact energies, the clusters can be pinned on the graphite surface when the impact energy exceeds a critical (threshold) value, thus allowing the fabrication of monodispersed cluster arrays which are stable at room temperature (and above). One application of such cluster arrays is to bind protein molecules; atomic force microscopy (AFM) measurements in buffer solution demonstrate dispersed arrays of both chaperonin and horseradish peroxidase molecules on graphite substrates decorated with size-selected Au N + clusters.