Effect of Tb Doping on Structural and Electrical Properties of BiFeO3 Thin Films Prepared by Sol–Gel Technique

Bi1−xTbxFeO3 thin films were prepared on SnO2 (fluorine doped tin oxide) substrates by a sol–gel method. The structural and electrical properties of the BiFeO3 thin films were characterized and tested. The results indicated that the diffraction peak of the Tb-doped BiFeO3 films was shifted towards right as the doping amounts were increased. The structure was transformed from the rhombohedral to tetragonal/orthorhombic phase. The Bi0.89Tb0.11FeO3 thin film showed the well-developed P–E loops, which enhanced remnant polarization (Pr = 88.05 μC/cm2) at room temperature. The dielectric constant and dielectric loss of Bi0.89Tb0.11FeO3 thin film at 100 kHz were 185 and 0.018, respectively. Furthermore, the Bi0.89Tb0.11FeO3 thin film showed a relatively low leakage current density of 2.07 × 10−5 A/cm2 at an applied electric field of 150 kV/cm. The X-ray photoelectron spectroscopy (XPS) spectra indicated that the presence of Fe2+ ions in the Bi0.89Tb0.11FeO3 thin film was less than that in the pure BiFeO3.