Effect of Tb content on microstructure and ferroelectric properties of Bi4−x Tb x Ti3O12 thin films grown by sol–gel method

Abstract

The effects of Tb substitution on the structural and electrical properties of ferroelectric Bi4Ti3O12 (BTO) thin films grown on Pt/TiO2/SiO2/Si substrates by a sol–gel process have been reported. X-ray diffraction indicated A-site Tb substitutions did not change the polycrystalline bi-layered Aurivillius structure of the BTO, but a lattice distortion was observed. The leakage current behavior at room temperature of the films was studied and it was found that the leakage current density decreased from 10−2 to 10−4 A/cm2 with the increase of x under 150 kV/cm. The remnant polarization (2P r ) and dielectric constant (e r) increase firstly and then decreases with the increase of the Tb content. We observed a substantial increase in the remnant polarization (2P r ) with Tb substitution and obtained a maximum value of~60 μC/cm2 at an applied electric field of 500 kV/cm for x = 0.4. Moreover, this BTT-0.4 capacitor did not show fatigue behaviors after 1.0 × 1010 switching cycles, suggesting an anti-fatigue character.