Synthesis and properties of Cd-doped ZnO nanotubes

Cd-doped ZnO nanotubes with a Cd incorporation of about 3.3 at% were produced onto Au-catalyzed Si substrate through a process of first evaporating mixture of pure Zn and Cd powders and following oxidation under a wet condition. The most nanotubes have outer diameters of ∼150 nm, lengths of up to several micrometers, and wall thickness range ∼20 nm. The photoluminescence (PL) spectrum of the Cd-doped ZnO nanotubes exhibited a narrow weak ultra-violet (UV) near-band-edge (NBE) emission at 388 nm and a broad strong green emission at around 497 nm. The UV NBE emission of the Cd-doped ZnO nanotubes showed a slight red shift due to Cd substitution.