AuSb2 alloy formation on HOPG by successive deposition of Sb clusters and Au atoms

Abstract

The behaviour of gold atoms that alloy into amorphous antimony (aSb) islands is studied by transmission electron microscopy (TEM), selected-area electron diffraction (SAED), and energy dispersive X-ray spectroscopy (EDS). In a first step, antimony thin films are produced by low-energy cluster beam deposition (LECBD). The antimony clusters (of diameter ≈5 nm, with 2300 atoms) are generated in a thermal source by the gas aggregation technique and deposited onto highly-oriented pyrolitic graphite (HOPG). For cluster submonolayer coverage (<0.2 M.L.), the diffusion and interaction of clusters on substrate lead to the formation of amorphous ramified Sb islands, formed by the aggregation of spherical particles about 10 nm in diameter. In a second step, gold is vapour-deposited onto the aSb–HOPG substrate. The influence of gold atom deposition on the morphology of the islands is studied. Moreover, varying the gold thickness, we characterize the AuSb2 alloy formation.