MICROSTRUCTURE EVOLUTION OF GOLD ATOMIC AGGREGATES FABRICATED ON SILICONE OIL SURFACE

Abstract

Gold atomic aggregates are fabricated by vapor-depositing Au atoms onto a silicone oil surface and the microstructure evolution is investigated by atomic force microscopy (AFM) observation. It is found that the Au aggregates are composed of Au circular nanoparticles with diameter around 45 nm, which is independent with the nominal film thickness d. As d increases from 1 nm to 15 nm, the height of the nanoparticles increases from 15 nm to 25 nm, indicating the geometric shape of the Au nanoparticles evolves from plateau to spherical. Furthermore, the roughness analysis shows that the mean surface roughness increases linearly with d in the range of 1 nm–15 nm, which is quite different from the findings in Ag system. The anomalous microstructure evolution of Au aggregates suggests that the growth of Au aggregates may be dominated by the shadowing effect.