Self-organized growth of ZnO single crystal columns array

Freestanding high-oriented single crystal ZnO columns array were prepared at the temperature range of 920–980 °C by a simple two-step evaporation oxidation method without template introduced. The effects of releasing mode of zinc vapor to formation of ZnO columns array were evidenced. X-ray diffraction (XRD), scanning electron microscope (SEM), and photoluminescence (PL) were used to characterize the morphology, structure and optical property of the sample. A possible growth mechanism was proposed and the conversion from ZnO to ZnS was realized by a high-temperature sulfuration with columns array maintained.