Influence of film thickness on ferroelectric properties and leakage current density in lead-free Bi0.5(Na0.80K0.20)0.5TiO3 films

In this study, lead-free Bi-0.5(Na0.80K0.20)(0.5)TiO3 (BNKT) ferroelectric films, with different thicknesses on Pt/Ti/SiO2/Si substrates, were formed via chemical solution deposition at a crystallization temperature of 700 degrees C. X-ray diffraction analysis revealed the characteristic peaks of the rhombohedral symmetries. Ferroelectric properties and leakage current density of BNKT films were analyzed as a function of the thickness. When the thickness increased from 200 nm to 600 nm, ferroelectric properties and leakage current behavior of the films were remarkably improved. The remnant polarization (P-r) was enhanced from 2.37 mu C cm(-2) to 8.41 mu C cm(-2) at applied electric field of 150 kV cm(-1) and leakage current density (J) at electric field of 40 kV cm(-1) declined from 12.4 x 10(-4) A cm(-2) to 2.6 x 10(-4) A cm(-2).