Study On Growth Mechanism Of Zinc Oxide Nanowires In Aqueous Solution

In the bath environment at constant or varied temperature, ZnO nanowire arrays and independent ZnO nano/micron structures were grown on Si and glass substrates by aqueous solution method. The growth mechanism of ZnO nanowires were investigated.Firstly, ZnO nanowire arrays were grown by seed-aided aqueous solution method. ZnO seeds were fabricated by means of Evaporation-driven Seeds Deposition and Vertical Dip Coating (VDC), and the latter method gave relatively uniform result. The size-uniform and orientation-ordered ZnO nanowire arrays were grown from the seeds fabricated by the continuously VDC. The stripe and matts of ZnO nanowire arrays were grown from the seeds fabricated by the uncontinuously VDC. In addition, the influence of CuO seeds on ZnO nanowire arrays were investigated. ZnO nanowire arrays were grown from the mixed seeds of ZnO and CuO. Increasing CuO proportion in the mixed seeds has profound effect on ZnO nanowire arrays'density. Meanwhile, the influence of slit confined growth setup on ZnO nanowire arrays were also investigated. The results showed that the slit could affect the reactant concentration by influencing the fluid exchange around ZnO nanowires, thus leading to slowed growth rate of nanowires. In the whole, the growth mechanism of ZnO nanowire arrays were analysed.The understanding of ZnO nanowires'growth process was further improved by the analysis of discretely grown independent ZnO nano/micron rod structures. Unlike array growth mode, scattered ZnO nano/micron rod structures were grown on naked substrates without seed layer. Their morphological characteristics were analysed in observation of every growth individual. The common law and individual character were found by comprehensive analysis, in consideration of specific growth environment. By reasonable deduction of growth process, the underlying growth mechanism was intended. Meanwhile, the formation mechanism of special byproduct structure in ZnO growth was also analysed. It showed that ZnO nano/micron rod structures, whether simply individual or complex, appear to be grown from their very only common cores respectively, namely the original growth unit of zinc oxide. The diversity of original growth units in their structure and clustering configuration gave out the particularly diverse morphology, as observed. Finally, we saw that other ZnO special structures came out in the growth process through direct ZnO mutational transformation.