Influence of annealing temperature on physical properties of NaNbO3 thin films prepared by a water-based sol-gel process

Sodium niobate (NaNbO3, NNO) has attracted considerable attention as a potential lead-free candidate for high-density energy-storage capacitors. An economical, environment-friendly, and low-temperature-synthesized route of NNO films is highly desirable for practical applications. In this study, a novel water-based solgel route was designed for the growth of NNO films, and the effects of annealing temperatures (400-600 degrees C) on microstructure and physical properties were investigated. By increasing the annealing temperature, the quality of (001)-preferred NNO films was improved, but a higher annealing temperature (e.g., 600 degrees C) induced the secondary phase, resulting in the degradation of electrical properties. As annealed at the optimum temperature of 500 degrees C, the highly (001)-preferred NNO film possessed advantageous characteristics including the largest difference between maximum polarization and remanent polarization (e.g., 26 mu C/cm(2) at 300 kV/cm), the maximum dielectric constant, and the minimum dielectric loss (e.g., 241.68 and 0.06 at 10 kHz). These results demonstrate a promising option toward solution-processed Nb-containing perovskite oxides through water-based sol-gel routes for energy-relevant applications. Published under license by AIP Publishing.