Formation and evolution of self-assembled crystalline Si nanorings on (001)Si mediated by Au nanodots

The growth of high-density Si nanorings has been achieved on ultrathin Au films on silicon substrate. Nanorings, which are gold-free and epitaxially grown on (001) Si, had a narrow distribution of height and diameter of 1.4 +/- 0.3 and 24.9 +/- 4.0 nm, with a density of 4.3x10(10) cm(-2). In situ ultrahigh-vacuum transmission electron microscopy revealed that the formation of nanorings involves a mechanism mediated by Au nanodots and evaporation of Au-Si eutectic liquid droplets at high temperature. The process promises to be an effective nanofabrication technique to produce high-density and uniform-sized nanorings. (c) 2005 American Institute of Physics.