Preparation and optimization of vertically arrayed zinc oxide nanorods

A two-step method for growing vertical zinc oxide nanorod arrays on indium tin oxide (ITO)-coated glass substrates is proposed. First, a zinc oxide seed layer was formed on the ITO substrate by simple dipcoating combined with the Czochralski method, and then vertical zinc oxide nanorod arrays were obtained by a hydrothermal method. The nanorod arrays were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) and energydispersive X-ray spectroscopy (EDS). The effects of the precursor concentration, sol-aging time, hydrothermal reaction time, and cycle times of the dip-coating and hydrothermal reaction on the structure and surface morphology of the zinc oxide nanorod arrays were investigated. The results show that the length and diameter of zinc oxide nanorod arrays increased with the increasing precursor concentrations, sol-aging time, and hydrothermal reaction time. Good vertical zinc oxide nanorod arrays were obtained under the optional growth conditions, i.e., three hydrothermal reactions for 150 min, three rounds of dip-coating, 0.5 mol L^–1 precursor solution concentration, and 24 h aging.