Synthesis of uniform hexagonal prismatic ZnO whiskers

Large-quantity growth of hexagonal prismatic ZnO whiskers was achieved via a process of first reduction and following oxidation of a ZnS powder at 1300 °C. The products were characterized using X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, and photoluminescence spectroscopy. The as-grown whiskers appear to be structurally uniform with an individual width of around 350 nm and length of up to 15 μm, and they are single crystalline in nature. All of them have hexagonal cross sections and grow along the [001] crystallographic direction. Room-temperature photoluminescence spectra of the whiskers reveal a strong and sharp UV emission band at 388 nm and a weak and broad green emission band at 515 nm. Possible growth mechanisms of the ZnO whiskers were discussed.