Synthesis of the hexagonal pillar shaped ZnOs using a hydrothermal method

This study focused on the stable synthesis to obtaining nanometer sized hexagonal pillar-like ZnO, which can be utilized as LED (light emission device) materials. Various zinc oxides were successfully synthesized by hydrothermal treatment at 150, 200 and 250 °C for 8 h, with their morphologies controlled at pHs 9, 11 and 13, by the addition of ammonium hydroxide. The SEM (scanning electron microscopy) results reveal that the as-prepared particles at pH 13 and 200 °C for 8 h were a complete hexagonal pillar shaped. On the other hand, the morphology was flower shaped at lower pH and temperature. This result indicates that hexagonal pillar shaped ZnO can be easily formed higher pH and temperature reaction conditions. Two types of emitting band for all ZnO samples were observed at around 400 nm (violet) and above 550 nm (green) in the photoluminescence (PL) spectra.