Study of the Growth and Concentration Fields of ZnO Nanostructures in a Double-Tube Furnace

Abstract

ZnO nanostructures were prepared by chemical vapor deposition (CVD) in a double-tube furnace. The effects of the carrier gas and oxygen flow rates on the morphology and yield of the products are described. The concentration distributions of O₂ and Zn vapor were simulated by the computational fluid dynamics (CFD) software FLUENT. The experimental and simulation results revealed that the content of Zn was much greater than that of O₂ at different deposition positions and that the deposition reaction was mainly controlled by the O₂ concentration. The reaction occurred mainly on the outside of the inner tube with the increasing N₂ flow. In contrast, the reaction occurred mainly on the inside of the inner tube with the increasing O₂ flow. A reduction of the carrier gas flow rate and an increase of the O₂ flow rate were both conducive to a morphology transition of the ZnO nanostructure from needle-like tetrapodal to nail-like tetrapodal.