Deposition of size-selected metal clusters generated by magnetron sputtering and gas condensation: a progress review

This paper presents a topical review of the production and deposition of size-selected metal clusters generated by magnetron sputtering and gas condensation. Clusters with up to 75 000 atoms can be obtained by controlling the gas pressure in the sput-tering source, prior to size selection with a novel (time-of-flight) mass filter. The clus-ters are deposited on the model graphite substrate to study the cluster–surface inter-action. Two regimes for cluster deposition have been identified at elevated impact energies: (i) ‘pinning ’ (ca. 10 eV per atom) and (ii) implantation (ca. 100 eV per atom). Of particular importance is the pinning regime, since this allows the fab-rication of monodispersed cluster arrays, which are stable against diffusion at room temperature (and above). The deposition of size-selected metal clusters represents a novel method of preparing surface nanostructures, with potential applications includ-ing model catalyst studies and the immobilization of biological molecules