Multipod ZnO 3D microstructures

ZnO 3D microstructures with nano-multipod have been self-assembly synthesized on a post-annealed Ag-coated silicon substrate by sintering the mixture of ZnO and graphite powders in Ar flow. SEM images show that the microstructure has a spherical core and multiple radial nanorods grown around its outside with diameter of about 1-2 mu m and 50-200 nm, respectively. XRD investigation shows the ZnO multipods are of a wurtzite structure. The room temperature photoluminescence spectrum of the microstructures reveals a strong broad green emission band at 530 nm. It is found that the post-deposition annealing treatment of the Ag thin film is a key factor to control the formation of ZnO 3D microstructures. The possible growth process based on VLS mechanism is proposed. (c) 2007 Elsevier B.V. All rights reserved.