Electrochemical growth of ZnO nanoplates.

ZnO films were grown on polycrystalline Zn foil by cathodic electrodeposition in an aqueous zinc chloride/calcium chloride solution at 80 °C. Variation in the electrochemical parameters resulted in a variation in growth morphology from 1D (nanorods), 2D ('nanoplates') to 3D crystal growth. An as-received or mechanically polished substrate proved the most suitable substrate finish and allowed more highly aligned, dense structures to be grown; in contrast, electropolished substrates formed inhomogeneous deposits. Substrate annealing gave rise to large homogenous areas of nanorod deposition. Two-dimensional sheet growth was found to occur in conjunction with nanorods under specific electrochemical conditions. Hexagonal 'plates' approximately 50 nm in thickness and several microns in diameter were formed normal to the substrate.