One-dimensional growth of zinc oxide nanostructures from large micro-particles in a highly rapid synthesis

Large and irregularly-shaped zinc oxide (ZnO) micro-particles commonly found in a high-temperature vapor-phase process known as the catalyst-free combust-oxidized mesh (CFCOM) process, play a crucial role as nucleation hosts for ZnO one-dimensional (1D) nanostructures, especially nanometric wires and rods. Nanowires and nanorods tend to grow from the hillocks of the large micro-particles whereby these hillocks serve as nucleation sites for the acicular structures. Nanowires with aspect ratios exceeding 5 are the most common 1D structures that grow from pillar-like hillocks, while triangular hillocks are probable nucleation hosts for nanorods. The ZnO nanostructures possess a polycrystalline nature with photoluminescent emission in the UV band-edge and visible regimes. A novel and non-destructive electrical resistance measurement method is introduced in that the 1D ZnO nanostructures exhibited very high G Omega resistance that is over five times higher than that of commercial ZnO. A growth model is proposed to offer a probable explanation for the fascinating rapid growth of 1D nanostructures originating from large ZnO micro-particles. The ZnO particles in this work were synthesized using 5-ton industrial furnaces via a university-industry joint effort. (C) 2011 Elsevier B.V. All rights reserved.