A simple, low-temperature fabrication method of highly (100)-oriented (Na_0.85K_0.15)_0.5Bi_0.5TiO₃thin films with outstanding electric properties

In this paper, we propose a simple but effective method to prepare high-quality (100)-oriented (Na_0.85K_0.15)_0.5Bi_0.5TiO₃(NKBT) thin films with outstanding electric properties by a sol-gel spin-on technique. By introducing a LaNiO₃seed layer between the substrate and thin film, we simultaneously achieved crystallization at temperatures as low as 450 °C and controlled orientation. X-ray diffraction and X-ray reflectometry indicated that the NKBT/LNO thin film annealed at 500 °C was highly (100)-oriented, and had clear interfaces without diffusion, effectively reducing the dielectric constant and leakage current. Additionally, due to its high (100) orientation and clear interface, the NKBT thin film annealed at 500 °C had high displacement and a high pyroelectric coefficient, giving it a higher pyroelectric figure of merit than those of previously reported films. This study provides a new and simple method for preparing highly oriented lead-free thin films at low temperatures, and it extends the possible applications of these films to integration with silicon substrates.