Fig. 1From: Enhanced Photoelectrochemical Activity of ZnO-Coated TiO2 Nanotubes and Its Dependence on ZnO Coating ThicknessTop-view and cross-sectional SEM images of a bare TiO2 NTs, b 10-cycle ZnO/TiO2 NTs, and c 25-cycle ZnO/TiO2 NTsBack to article page