Fig. 5From: Enhanced Photoelectrochemical Activity of ZnO-Coated TiO2 Nanotubes and Its Dependence on ZnO Coating ThicknessUV–visible absorption spectra of bare TiO2 NTs (1), 10-cycle ZnO/TiO2 NTs (2), and 25-cycle (3) ZnO/TiO2 NTsBack to article page