Control on the morphologies of tetrapod ZnO nanocrystals

Control on the morphology, including the size and shape of individual legs, of tetrapod ZnO nanocrystals is of importance for tuning their properties. We studied systematically the influences of the Zn vapor oxidization time and temperature, the ZnO condensation time and temperature on the morphologies of tetrapod ZnO nanocrystals fabricated through zinc vapor oxidization followed by ZnO condensation. We found that the variation of ZnO condensation temperature and time can change the tetrapod ZnO nanocrystal growing behavior dramatically. The increase of the condensation time leads to the morphology transition of the tetrapod legs from hierarchical hexagonal (HH) to uniform hexagonal (UH) prism. The tetrapod ZnO nanocrystal with uniform UH prism legs can only be obtained at relatively higher condensation temperature and longer condensation time. While the Zn vapor oxidization time and temperature do not affect the morphology of the tetrapod ZnO nanocrystals noticeably.