The microstructure, ferroelectric and dielectric behaviors of Na0.5Bi0.5(Ti,Fe)O3 thin films synthesized by chemical solution deposition: Effect of precursor solution concentration

Fe-doped Na0.5Bi0.5TiO3 (NBTFe) thin films were prepared directly on indium tin oxide/glass substrates using a chemical solution deposition method combined with sequential layer annealing. The X-ray diffraction, scanning electron microscopy and insulating/ferroelectric/dielectric measurements were utilized to characterize the NBTFe thin films. All the NBTFe thin films prepared by four precursor solutions with various concentrations of 0.05, 0.10, 0.20 and 0.30 M exhibit polycrystalline perovskite structures with different relative intensities of (l00) peaks. A large remanent polarization (Pr) of 33.90 μC/cm2 can be obtained in NBTFe film derived with 0.10 M spin-on solution due to its lower leakage current and larger grain size compared to those of other samples. Also, it shows a relatively symmetric coercive field and large dielectric tunability of 36.34%. Meanwhile, the NBTFe thin film with 0.20 M has a high energy-storage density of 30.15 J/cm3 and efficiency of 61.05%. These results indicate that the electrical performance can be controlled by optimizing the solution molarity.