Influences of ZnO sol-gel thin film characteristics on ZnO nanowire arrays prepared at low temperature using all solution-based processing

Abstract

Zinc oxide (ZnO) nanowire arrays with controlled nanowire diameter, crystal orientation, and optical property were prepared on sol-gel ZnO-seed-coated substrates with different pretreatment conditions by a hydrothermal method. The vertical alignment, crystallinity, and defect density of ZnO nanowire arrays are found to be strongly dependent on the characteristics of the ZnO thin films. Field-emission scanning electron microscopy, energy dispersive spectroscopy, x-ray diffraction, and room temperature photoluminescence were applied to analyze the quality of the ZnO nanowire arrays. The annealing temperature of the ZnO thin film plays an important role on the microstructure of the ZnO grains and then the growth of the ZnO nanowire arrays. The x-ray diffraction results indicate that the thin film annealed at the low temperature of 130°C is amorphous, but the thereon nanowire arrays are high-quality single crystals growing along the c-axis direction with a high consistent orientation perpendicular to the substrates. The as-synthesized ZnO nanowire arrays via all solution-based processing enable the fabrication of next-generation nanodevices at low temperature.