Hierarchical type-II heterostructures were fabricated on FTO glass based on vertically aligned ZnO nanorod arrays (NRAs) decorated with CdS nanowires (NWs) branches using a sequential hydrothermal growth (ZnO NRAs), vapor-liquid-solid approach (CdS NWs). The cathodoluminescence (CL) properties of the fabricated ZnO/CdS heterostructure demonstrated the good quality of the material as well as luminescence quenching thus suggesting type II band alignment between CdS and ZnO. Photoelectrochemical cells were fabricated with an effective electrode area similar to 0.2 cm(2) resulting in 0.65 V V-oc and 1.15% efficiency for devices based on ZnO NRAs/CdS NWs heterostructures using a thin layer (similar to 2 nm) of Al2O3 at the interface between ZnO nanorods and CdS branches. (C) 2013 Elsevier B.V. All rights reserved.