Self-Assembled Si-Ge Nanorings with Size and Composition-Control

Self-assembled single-crystal nanorings (NRs), as small as 10 nm, on Si and Si-Ge alloys have been fabricated by the mediation of Au nanodots. Si-Ge thin films were transformed into Si-Ge nanorings (silicon nanorings doped with controlled amount of Ge) with the assistance of Au catalysts deposited directly onto the thin film with a simple process. The mechanism of nanoring formation involves the mediation by Au nanodots and evaporation of Au-Si (Au-Si-Ge) eutectic liquid droplets at high temperatures. The process promises to be an effective nanofabrication technique to produce high density and uniform in size Si and Si-Ge nanorings