Figure 5.

FESEM images of TiO₂ nanotubes fabricated in glycerol containing 0.5 wt% NH₄F and 0.2 wt% H₂O via second-step anodization: (a) top surface view at low magnification, (b) top surface view at high magnification, (c) top surface view of patterned Ti-substrate anodized for 10 min, (d) cross-sectional view at low magnification, (e) cross-sectional view of the marked area at high magnification.