Zinc oxide nanopillars with a single crystalline structure on the indium tin oxide substrate were prepared by using an electrodepositing process in lower concentrations of aqueous Zn(NO3)(2) and 0.1 M KCl solutions. Surface structure and crystal orientation of the prepared ZnO films were characterized by scanning electron microscopy, transmission electron microscopy, and X-ray diffraction, respectively. By varying the electrolyte composition, the morphology and crystal orientation of ZnO films may be changed dramatically. Well-oriented ZnO nanopillars can be obtained at a relatively low concentration of zinc ion in the electrolyte, and at a lower potential. A bandgap energy change of grown ZnO with different Zn (NO3)(2) concentrations was observed. The effects of electrodepositing potential, deaerating, and annealing are also discussed. (c) 2006 The Electrochemical Society.