Preparation and characterization of Ca0.18Na0.32Bi0.50TiO3 ferroelectric thin films by metalorganic solution deposition

Ca0.18Na0.32Bi0.50TiO3 (CNBT) ferroelectric thin films were prepared by metalorganic solution deposition on silicon substrate and annealed at different temperatures. The morphology and structure of the films were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The crystal structure of Ca-doped Na0.50Bi0.50TiO3 films shows no obvious lattice distortion compared with that of un-doped one. The optimal heat treatment process for CNBT films were determined to be high-temperature drying at 400 oC for no less than 15 min followed by annealing at 600 oC for 5 min, which leads to the formation of compact films with uniform grains of 30-50 nm. Ferroelectric property measurement shows that the remanent polarization of CNBT films is 18 times higher than that of un-doped Na0.50Bi0.50TiO3 (NBT) thin films.