Formation and self-organization of nanometer-scale Au particles on graphite by vacuum deposition in iodine vapor

Vacuum depositions of Au on highly oriented pyrolytic graphite (HOPG) and SiO2 substrates in iodine vapor of 1 × 10–4 Torr give rise to formation of dispersed nanoscale Au particles at room temperature. The iodine is physisorbed on the Au surface and prevents the Au particles from coalescing. The mean diameter of Au particles on highly oriented pyrolytic graphite (HOPG) is about 40 nm, which is larger than that on SiO2 The particles on HOPG have a narrower and more uniform size distribution than those on SiO2. Radial distribution function of the particles on HOPG showed many well-defined peaks, whereas that on SiO2 had only one peak, indicating highly structured deposition on HOPG by iodine adsorption.