426457.fig.001a
(a)
426457.fig.001b
(b)
426457.fig.001c
(c)
426457.fig.001d
(d)
426457.fig.001e
(e)
426457.fig.001f
(f)
Figure 1: Top-view SEM images of ZnO NWs grown on ((a) and (c)) FTO (samples FTO-A and FTO-B, resp.), (d) sapphire, and ((e) and (f)) Si (samples Si-A and Si-B, resp.). (b) Cross-sectional SEM image of the FTO-A sample in (a). The insets reveal that the NW diameters range between 30 and 90 nm.