Effect of cluster size on phase stability in nm-sized Au-Sb alloy clusters

The effect of cluster size on the phase stability in nanometre (nm)-sized Au-Sb alloy clusters has been studied by means of transmission electron microscopy (TEM), in order to see the difference in the phase stability between a bulk material and the corresponding nm-sized cluster. When the cluster size is reduced below approximately 6 nm in mean diameter, it is difficult to form distinct interfaces between two different phases (i.e. solid solution and AuSb2) in the interior of individual Au-Sb alloy clusters. Analytical electron microscopy using an electron probe of approximately 1 nm in diameter revealed that the solid solubility of antimony in a few nm-sized gold clusters increases by at least one order of magnitude compared to that for the corresponding bulk material.