Effect of thermal treatment on the structure and optical properties of biomimic hierarchical ZnO column arrays

In order to study the effect of thermal treatment on the structure and optical properties of biomimic hierarchical ZnO column arrays, the as-grown biomimic hierarchical ZnO column arrays were annealed in air from 200 to 650 °C, and the change of their hierarchical structure was observed by the high-resolution transmission electronic microscopy image. The UV-vis spectra exhibited an interesting change of the structure with different annealing temperatures. Photoluminescence intensity of annealed biomimic arrays was increased at about 520 nm. The mechanism of visible emission was also discussed.