Figure 4.

Cross-sectional FE-SEM images of a bare FTO substrate, b pristine TiO2/FTO, and c O2 ion-irradiated TiO2/FTO. The thickness of the pristine and irradiated TiO2 was about 1.1 and 0.67 μm, respectively. (Inset: images in 100 nm scale.)

Sudhagar et al. Nanoscale Res Lett 2011 6:30   doi:10.1007/s11671-010-9763-2