The properties of clusters are different from those corresponding to bulk matter that gains an interest in use of cluster beams for formation of nanostructured materials. With cluster ion beams it is easy to control cluster size, their energy and to a certain extent their spatial deposition over the surface. However, energetic cluster deposition is a poorly studied subject so far. More fundamental studies should be carried out to clarify the physics behind multiple-collision processes and collective phenomena in cluster-surface interaction.
The laser ablation technique is used to produce metal clusters. This cluster source is attached to an existing cluster implantation and deposition apparatus[1]. The second harmonic (532 nm) of a Nd:YAG laser is used to ablate the metal from a rotating rod and the carrier (He or Ar) gas cools the vaporised material which leads to the cluster formation. The gas/cluster mixture is expanded into vacuum resulting in further cooling and cluster formation. The clusters are collimated into a beam using a skimmer and then ionised with an excimer laser.
The clusters can be mass-selected and accelerated up to 20 keV/cluster and then deposited on any substrate. Size selected clusters of Co and Fe energetically deposited (pinned) on various surfaces can be used as catalysts to control the growth of carbon nanotubes. Formation of optical sensors and sophisticated labels can be achieved using energetic deposition of size selected noble metal clusters followed by co-deposition of an optically transparent coating layer. Also shallow imbedding of metal clusters into soft materials, like polymers, will be tested.
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