The growth of SiGe quantum rings in Au thin films on epitaxial SiGe on silicon

Self-assembled SiGe quantum rings (QRs) on Si 0.8Ge 0.2 substrate has been formed by thermal annealing of the samples with capping Au thin films at 1100 °C in N 2 ambient. Miniature quantum rings have a narrow distribution of diameter and height of 27.9±1.7 and 1.53±0.10 nm, respectively. The formation of quantum rings was found to be mediated by the Au nanoparticles. As the size of Au nanoparticles can be adjusted, the method promises to be an effective technique to produce high density, uniform in size quantum rings.