Preferential nucleation of cobalt nanoclusters on the faceted rhenium (12¯31) surface

We have studied the preferential nucleation of cobalt nanoclusters on oxidized faceted rhenium(12¯3 1) by means of Auger electron spectroscopy (AES), low energy electron diffraction (LEED), and scanning tunneling microscopy (STM). Preferential nucleation means that the Co nanoclusters form at specific sites on the substrate. In contrast to previous nanostructure studies of preferential nanocluster nucleation in metal on metal experiments, we use a surface that is both oxidized and faceted to form a nanotemplate. It is shown that for cobalt coverage between 1.6 ML and 3 ML, preferential nucleation of cobalt nanoclusters occurs on this faceted surface. It is also shown that by varying the parameters of cobalt coverage, facet width and annealing temperature, the cobalt nanocluster size can be varied. The cobalt nanocluster system may prove to be a model system for future studies of different substrates and overlayers more relevant to catalytic reactions.M.S.Includes bibliographical references (p. 56-57)