In situ observation of ZnO nanowire growth on zinc film in environmental scanning electron microscope.

In situ uniform growth of ZnO nanowires was realized and monitored at real time by heating zinc film in an environmental scanning electron microscope. Better controllability and repeatability were obtained by using zinc film as source material compared to traditionally used zinc powder. Morphology of the as-grown ZnO nanowires was found to depend on both the growth temperature and holding time. Low temperature (500 °C) and short growth time (∼20 min) favor one-dimensional nanowire growth, whereas longer holding time (>40 min) or higher temperature (700 °C) lead to nanosheet growth. The results suggest that the zinc vapor partial pressure is vital in determining the final morphology. These results help to give more insights into the mechanism of ZnO nanowire synthesis. [ABSTRACT FROM AUTHOR]