Growth of high-quality, uniform c-axis-oriented zinc oxide nano-wires on a-plane sapphire substrate with zinc oxide templates

High-quality, vertically aligned zinc oxide (ZnO) nano-wires were grown by the vapour-transport method on (11 (2) over bar0) (a-plane) sapphire substrate covered by a uniform ZnO nano-crystalline seed layer which was deposited in a preceding growth step via simple chemical vapour deposition. A thin layer of close-packed nano-seeds with an average size of 12 nm was formed rapidly on the substrate by sublimation and thermal decomposition of zinc acetate dihydrate as the precursor at moderate temperatures and pressures. Subsequently, growth of ZnO nano-wires was performed by a carbo-thermal vapour-transport method yielding nano-wires with high reproducibility and homogeneity. The as-grown, c-axis-oriented nano-wires exhibit excellent luminescence properties and perfect alignment with respect to the substrate surface. (C) 2008 Elsevier Ltd. All rights reserved.