Orientation effect in electronic properties of silicon wires

Abstract

Electronic properties of (100), (110), and (111) oriented H-terminated silicon quantum-size wires have been calculated within the self-consistent LCAO method. The quantum confinement induced direct band gap only appears in the (100) wires. Surface silicon d and p electrons are found to be responsible for the bottom of the conduction band while the top of the valence band are formed by p electrons of the core atoms. Possible reconstruction of the wire surface is discussed.