Arrays of ZnO/ZnxCd1-xSe Nanocables: Band Gap Engineering and Photovoltaic Applications

Arrays of ZnO/ZnxCd1-xSe (0 <= x <= 1) core/shell nanocables with shells of tunable compositions have been synthesized on fluorine-doped tin oxide glass substrates via a simple ion-exchange approach. Through the effects of stoichiometry and type H heterojunction, optical absorptions of the nanocable arrays can be controllably tuned to cover almost the entire visible spectrum. Lattice parameters and band gaps of the ternary ZnxCd1-xSe shells were found to have respectively linear and quadratic relationships with the Zn content (x). These ZnO/ZnxCd1-xSe nanocable arrays are further demonstrated to be promising photoelectrodes for photoelectrochemical solar cells, giving a maximum power conversion efficiency up to 4.74%.