Photoirradiation Caused Controllable Wettability Switching of Sputtered Highly Aligned c-Axis-Oriented Zinc Oxide Columnar Films

Figure 2

Top view SEM images for the ZnO thin films with deposition powers of (a) 50, (b) 75, (c) 100, and (d) 150 W, respectively. The contact angle images for different ZnO thin films corresponded to the right side denoted by (e), (f), (g), and (h), respectively.