Low temperature hydrothermal growth and optical properties of ZnO nanorods

Well-faceted hexagonal ZnO nanorods have been synthesized by a simple hydrothermal method at relative low temperature (90 degrees C) without any catalysts or templates. Zinc oxide (ZnO) nanorods were grown in an aqueous solution that contained Zinc chloride and ammonia (25%). Most of the ZnO nanorods show the perfect hexagonal cross section and well-faceted top and side surfaces. The diameter of ZnO nanorods decreased with the reaction time prolonging. The samples have been characterized by X-ray powder diffraction (XRD) and scanning electron microscopy (SEM) measurement. XRD pattern confirmed that the as-prepared ZnO was the single-phase wurtzite structure formation. SEM results showed that the samples were rod textures. The surface-related optical properties have been investigated by photoluminescence (PL) spectrum and Raman spectrum. Photoluminescence measurements showed each spectrum consists of a weak band ultraviolet (UV) band and a relatively broad visible light emission peak for the samples grown at different time. It has been found that the green emission in Raman measurement may be related to surface states. (c) 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim