Preparation and Strong Ultraviolet Luminescence Performance of Worm-Like ZnO on Sapphire Substrates

350 nm polystyrene microspheres (PSs) are prepared on sapphire substrates as masks by nanosphere lithography technique, and then ZnO thin films are grown on PS/Al2O3 and Al2O3 substrates by reactive radio frequency magnetron sputtering method, respectively. X-ray diffraction analysis, scanning electron microscope observation, and photoluminescence (PL) test are used to measure two kinds of samples after annealing; the PS mask is removed from the Al2O3 substrate. The results show that the grains of the ZnO thin film grown on the PS/Al2O3 (sample 1) are obviously worm-like; the grains of the ZnO thin film directly grown on the Al2O3 substrate (sample 2) show incomplete hexagonal prism shape. Although the crystallization of sample 2 is better than that of sample 1, the intensity of near band edge photoluminescence peak of sample 1 around 362 nm is 43 times stronger than that of sample 2.