Fullerene-structured nanowires of silicon

Silicon vapor from a magnetron sputter source was deposited onto highly oriented pyrolytic graphite, resulting in the formation of nanoscale wires. The structures were analyzed by scanning tunneling microscopy. The wires are from 3 to 7 nm in diameter and at least 100 nm long. They tend to be assembled parallel in bundles. In order to understand the observed quasi-one-dimensional structures, diamondlike and fullerenelike wire models are constructed. Molecular-orbit calculations yield binding energies and band gaps of such structures, and lead us to propose a fullerene-type ${\mathrm{Si}}_{24}$-based atomic configuration for nanowires of silicon.