Hydrothermal growth of ZnO nanostructures using sodium hydroxide as a source of hydroxide ion

Abstract In this work, ZnO nanostructures were hydrothermally grown on ITO/glass substrates with AZO seed layer. The chemical agents to grow nanostructures were zinc nitrate and sodium hydroxide as precursors of zinc and hydroxide ions, respectively. The molar ratios of zinc to hydroxide ions were varied to be 10:10, 10:20, 10:30, and 10:40 mM with and without hexamine. Moreover, the ZnO nanorods were subsequently grown on ZnO nanostructures which were fabricated with molar ratio of 10:40. Then, all samples were characterized by FESEM, XRD and UV-vis to study the morphology, crystalline quality, and optical property, respectively. The results showed that the morphology of nanostructures was highly dense and uniform when hydroxide ions were obtained from sodium hydroxide. When the concentrations of hydroxide ions were varied, they affected the diameter and surface density of nanostructures. Finally, the ZnO nanorods showed high uniformity on ZnO nanostructure. The estimated surface area of ZnO nanorods on nanostructures was more than that of ZnO nanorods on seed layer.