Seed layer-free electrodeposition of well-aligned ZnO submicron rod arrays via a simple aqueous electrolyte

A potentiostatic electrodeposition technique was used to directly fabricate large-scale, well-aligned, and single-crystalline submicron ZnO rod arrays on tin doped indium oxide glass substrate without a pre-prepared seed layer of ZnO from an aqueous solution only containing zinc nitrate. The effects of electrochemical parameters, such as electrodeposition potential, electrodeposition duration, solution temperature, and precursor concentration, on the orientation, morphology, aspect ratio, and growth rate of ZnO rod arrays were systematically investigated. Results show that submicron ZnO rod arrays with (0 0 0 2) preferred orientation and perfect crystallization were obtained when electrodeposition potential was in the range from -0.6 to -1.1 V and solution temperature was controlled above 60 °C. Both high solution temperature and low precursor concentration resulted in the decrease in rod diameters. Photoluminescence measures showed that small diameter and nanotips of ZnO rod arrays should be responsible for strong and sharp ultraviolet emission in the room temperature photoluminescence spectra.