Influence of Excess Potassium on Structural and Ferroelectric Properties of Lead-Free Bi_0.5K_0.5TiO₃ Thin Films

Abstract

Lead-free Bi0.5K0.5TiO3 (BKT) ferroelectric films were synthesized on Pt/Ti/SiO2/Si substrates via the chemical solution deposition. The influence of the excess potassium on the microstructures and the ferroelectric properties of the films was investigated in detail. The results showed that the BKT films have reached the well-crystallized state in the single-phase perovskite structure with 20 mol.% excess amount of potassium. For this film, the ferroelectric properties of the films were significantly enhanced. The remnant polarization (Pr) and maximum polarization (Pm) reached the highest values of 9.4 μC/cm2 and 32.2 μC/cm2, respectively, under the electric field of 400 kV/cm.