SEM images of the synthesized arrays of ultralong ZnO nanowires by the CVD process. The digital image in (a) shows a typical sample prepared by the CVD process after a reaction time of 60 min. The SEM images in (b), (c), (d), (e), and (f) display the length and distribution of the ZnO NW arrays for different reaction times of the CVD process. The lengths of the ZnO NW arrays were about 150, 175, 200, 250, and 310 μm corresponding to the reaction times of 22, 30, 40, 50, and 60 min, respectively.
Fang et al. Nanoscale Research Letters 2012 7:197 doi:10.1186/1556-276X-7-197