Photoluminescence of ZnO nanowires grown on sapphire (1 1 (2)over-bar-0) substrates

Abstract

ZnO nanowires were fabricated on c-plane (0 0 0 1), a-plane (1 1 (2) over bar 0) sapphire, and boron doped p-type (1 0 0) Si substrates in vacuum furnace by simple physical vapor deposition. Room temperature photo luminescence spectra of the nanowires show the near band-edge emission and the deep-level green light emission. The ZnO nanowires formed on sapphire (1 1 (2) over bar 0) substrates exhibited enhancement on optical properties and better crystalline structures than those of nanowires grown on other substrates. The formation mechanism and the effect of substrate direction on structural and optical properties of the nanowires are discussed. (C) 2006 Elsevier B.V. All rights reserved.