Growth Mechanism of Zinc Oxide Nanowires by Geometrical Selection and the Effect of Zinc Oxide Binding Peptides

T.Y. Olson, A.A. Chernov, K.E. Murphy, J.H. Satcher, T.Y. Han
Lawrence Livermore National Laboratory, US

Keywords: zinc oxide, nanowire array, growth mechanism, geometrical selection


Zinc oxide nanowire arrays have potential in many important applications such as solar cells, sensors, and nanogenerators and such devices require the controlled structural fabrication to obtain the desired chemical and mechanical properties. Zinc oxide nanowire arrays were hydrothermally grown on a Si(100) substrate coated with a randomly oriented seed layer to assess the validity of a theoretical model based on geometrical selection. The theory states that randomly oriented crystallites can be grown as an oriented film or array of nanowires due to a preferential growth direction; in the case of ZnO, the c-axis. To examine this growth phenomenon experimentally, ZnO nanowire arrays were grown and their length and crystal density measurements as a function of growth time obtained. A detailed analysis found the results to match closely with the prediction based on the geometrical selection model. The close fit between experiment and theory indicated that geometrical selection could be used as a model to explain the mechanism of randomly oriented seeds evolving into an oriented film. Such understanding will allow improved interpretation of the effects of certain parameters, such as substrate type, on the resulting orientation of the nanowire array.