High-Quality, Reproducible ZnO Nanowire Arrays Obtained by a Multiparameter Optimization of Chemical Bath Deposition Growth

ZnO nanowire arrays represent an important multifunctional platform in nanotechnology with a diverse set of emerging applications. Many parameters and conditions are involved in the growth process affecting quality and reproducibility and hence the functionality of the nanowire arrays. Therefore, the fabrication of high-quality arrays is challenging and demands fastidious optimization. A multi parameter optimization of the growth process is presented here using the chemical bath deposition method of ZnO nanowires on seeded substrates. Parameters such as the seed layer morphology, ammonia and the polyelectrolyte capping agent concentrations, the molecular weight of the polyelectrolyte capping agent, the ammonia evaporation, the substrate placement into the reactor vessel, and the growth duration were adjusted to provide optimum nanowire arrays. Criteria used for selecting the optimum growth conditions include high aspect ratio, high nanowire length growth rate, good alignment, and minimum defect density in the crystal lattice. A critical comparison of the current achievements with the relevant current literature is presented. ZnO nanowire arrays fulfilling all of these criteria hold promise for the fabrication of devices with wide functionalities including solar cells, water splitting, photocatalysis for water purification, nanophotonics, and so on.