Atomic Layer Deposition of TiO₂ Nanocoatings on ZnO Nanowires for Improved Photocatalytic Stability

Figure 6

SEM images of ZnO, 20 cycles TiO₂@ZnO (incomplete coverage), and 1000 cycles TiO₂@ ZnO (complete and conformal coverage). (a) Top-down view of ZnO nanowire forest, (b) top-down view of 20-cycle TiO₂-coated ZnO nanowire forest, (c) top-down view of 1000-cycle TiO₂-coated ZnO nanowire forest, (d) single nanowire view of ZnO, showing hexagonal shape (single-crystalline), (e) single nanowire view of 20-cycle TiO₂ on ZnO, showing incomplete coverage, (f) conformally and fully coated 1000-cycle TiO₂@ZnO, (g) side view of ZnO nanowires, (h) side view of 20 cycles TiO₂@ZnO, and (j) side view of 1000 cycles TiO₂@ZnO.