Vapour transport growth of ZnO nanowires using a predeposited nanocrystalline template

Vapour transport growth of ZnO nanowires has been reported by a few groups. In most of the vapour transport deposition processes, 1-D ZnO nanostructures were produced at relatively high temperature (>900 deg. C) and a pre-deposited catalyst, such as Au, Co, or Sn, was needed to supply nucleation sites and provide the function of growth direction confinement. Here we have produced single crystal ZnO nanowires using a modified vapour transport method, in which a nanocrystalline ZnO template layer was first deposited by ultrasonic spray assisted chemical vapour deposition. The pre-deposited template was then used to grow ZnO nanowires by a traditional vapour deposition method. The nanowires were characterised using X-ray diffraction, field-emission gun scanning electron microscopy (FEG-SEM) and highresolution transmission electron microscopy (HRTEM). Several different morphologies of the ZnO nanowires, including branched wire growth, were observed and a possible growth mechanism was discussed