Optical properties of nanosized ZnO films prepared by sol-gel process

摘要

Nanosized ZnO films were prepared by sol-gel process on quartz substrates. The effects of sol concentration and annealing temperature on the surface morphology, microstructure and optical properties of the films were investigated. The results show that the sols remain stable and usable for spin-coating within 7d. The ZnO films have a homogeneous and dense surface with grain size about 30nm. The ZnO thin film annealed at 500°C for 1h from the sol with Zn concentration of 0.8mol/L shows an average transmittance of 94% in visible wavelength range. The optical band gaps in ZnO films by various annealing temperatures are from 3.265eV to 3.293eV. The violet emission located at 438nm is probably due to the recombination transitions relating to the interface traps at the grain boundaries.