Synthesis of tower-like ZnO structures and visible photoluminescence origins of varied-shaped ZnO nanostructures

Tower-like ZnO structures have been prepared by a simple carbon thermal reduction method and the possible growth mechanism of such structures was discussed. Comparing with microrods and nanowires, the photoluminescence images and spectra of tower-like ZnO were examined to understand the origins of their visible emissions, which is vital to future ultraviolet display devices. The visible photoluminescence locations of ZnO structures were studied by the near-field scanning optical microscopy. The experimental data indicate that the structure defects, surface impurities or dust, and adsorbed oxygen molecules can induce the visible emission of various ZnO nanostructures.