Facile synthesis of well-aligned ZnO nanowire arrays and their photoluminescence properties

Well-aligned zinc oxide (ZnO) nanowire arrays were directly fabricated on graphite sheet without using any metal catalyst. Well-crystalline wurtzite ZnO nanowires with average diameter of 80 nm grows vertically to graphite sheet. The photoluminescence (PL) measurement of the ZnO nanowire arrays presents strong ultraviolet emission band centered at 379.2 nm (3.3 eV) and very weak green emission, indicating the well-crystalline nature of the nanowire arrays. The growth mechanism is found to be a self-catalytic vapor-liquid-solid (VLS) process assisted by immiscibility of the zinc oxide-carbon system which can provide a thermodynamic driving force for the growth of the nanowire arrays. In addition, the influence of deposition temperature on the morphologies and photoluminescence properties of ZnO products was also investigated in detail. It is found that relatively low deposition temperature is contributed to the growth of well-aligned ZnO nanowire arrays. (c) 2008 Elsevier B.V. All rights reserved.