Alignment-controlled hydrothermal growth of well-aligned ZnO nanorod arrays

ZnO nanorod arrays (ZNAs) were prepared via a two-step seeding and solution hydrothermal growth process. Effects of preparing parameters such as seed layer, colloid concentration, substrate and precursor concentration, on the alignment control of ZNAs were systematically investigated. The deviation angle of ZnO nanorods was measured to evaluate the alignment of arrays. Results show that seed layer not only controls the vertical orientation of ZNAs, but also the compactness of ZNAs. Altering colloid concentration and substrate can influence the microstructure of ZnO seed layer and affect the ordered alignment of ZNAs. The precursor concentration has an insignificant effect on the alignment of ZNAs but has great impact on the morphology of ZNAs. Alignment-controlled and well-aligned ZnO nanorods with different diameter and aspect ratio can be obtained by properly controlling the preparing parameters. A growth mechanism was proposed for the growth of ZnO nanorods. (C) 2014 Elsevier Ltd. All rights reserved.