Stopping of energetic cobalt clusters and formation of radiation damage in graphite

• The interaction of energetic (up to 200 eV/atom) size-selected Con clusters with HOPG is studied both experimentally and theoretically. Etching of the radiation damage areas introduced by cluster impacts provides a measure of the depth to which the collision cascades are developed and allowes a comparison of these data with the molecular dynamics simulations. Good agreement between the experimental results and modelling is obtained. It is shown that the projected range of the cluster constituents can be linearly scaled with the projected momentum (the cluster momentum divided by surface impact area). With decrease of cluster energies to ca. 10 eV/atom the transition from implantation to pinning is suggested. It is found that even after quite energetic impacts residual clusters remain intact in the shallow graphite layer. These clusters can catalyse reaction of atmospheric oxygen with damaged graphite areas under the thermal heating that leads to the formation of narrow (5-15 nm) random in shape surface channels (trenches) in the top few graphene layers. Thus, small imbedded Co nanoparticles can be used as a processing tool for graphene.

Ämnesord

NATURVETENSKAP  -- Fysik -- Den kondenserade materiens fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Condensed Matter Physics (hsv//eng)

NATURVETENSKAP  -- Fysik -- Atom- och molekylfysik och optik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Atom and Molecular Physics and Optics (hsv//eng)

Nyckelord

cluster implantation

theory of impact phenomena

numerical simulations

atomic force microscopy

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