453517.fig.002a
(a)
453517.fig.002b
(b)
453517.fig.002c
(c)
Figure 2: The SEM image tilt at 45° SEM images of the ZnO nanoparticle on Al2O3 substrate after annealing at (a) 400°C, (b) 600°C, and (c) 800°C for 1 hour.