Seed-layer controlled synthesis of well-aligned ZnO nanowire arrays via a low temperature aqueous solution method

A simple and controllable method has been developed to synthesize well-aligned ZnO nanowire arrays on silicon and glass substrates in aqueous solution. A thin ZnO seed-layer coated with colloidal ZnO nanocrystals was introduced to control the density and orientation of ZnO nanowires. X-ray diffraction (XRD) and scanning electron microscopy (SEM) result show the high dense and well-aligned character of ZnO nanowires. The photoluminescence (PL) reveals the high crystal quality of the nanowires. It was found that the ZnO seed-layer can effect the size distribution, density and crystal structure of the nanowires. The growth mechanism of ZnO nanowires was also discussed.