Development and photoluminescence of ZnO-ZnS core-shell nanotube and nanorod arrays

After the wurtzite ZbS nanorods were synthesized by hydrothermal treatment in the presence of ethylenediamine (en) aqueous solutions at 200oC, ZnS-ZnO core-shell nanorods were readily obtained by annealing ZnS nanorods under oxygen at 650oC for 3-5 min. A strong broad peak in the 450-550 nm visible range was clearly detected and its peak intensity could be greatly enhanced after the ZnO shell was developed on hydrothermal ZnS nanorods. On the other hand, using AAO as a template, ZnS-ZnO core-shell nanotubes could be synthesized using atomic layer deposition process along with the sulfuration conversion of the ZnO nanotube array. This ZnO-ZnS core-shell nanotube structure could be confirmed by x-ray photoelectron spectroscopy (XPS) analysis. In addition, an enhanced UV emission along with the reduced visible emission was also detected for the ZnO/ZnS core-shell nanotubes.