Thickness-dependent ferroelectric behaviors of (111)-textured polycrystalline pseudo-cubic BiFeO3 thin films

Abstract

Preferentially (111)-textured polycrystalline BiFeO3 (BFO) thin films with different thicknesses were deposited on Pt(111)/Ti/SiO2/Si(100) substrates by using a pulsed laser deposition method. The structure of the BFO films was found to be pseudo-cubic with a lattice constant of 3.96 A based on the X-ray diffraction analysis. The (111)-textured polycrystalline BFO films exhibited good square-type P-E loops with a relatively large remnant polarization (2Pr) of 41 ∼ 54 µC/cm2 and a coercive field (2Ec) of 470 ∼ 510 kV/cm at an applied electric field strength of ±460 kV/cm. Even though the thicknesses of the films were changed, the changes in 2Pr and 2Ec were relatively small. The enhanced leakage current densities of the polycrystalline BFO films were observed to be at least comparable with those of other epitaxial BFO films. Furthermore, the leakage current densities of the films improved with increasing thickness.