Deposition-rate-dependent ferroelectric properties of epitaxially grown BaTiO3 thin films

Abstract We report the deposition-rate-dependent ferroelectric properties of BaTiO3 thin films fabricated through pulsed laser deposition. BaTiO3 thin films were epitaxially grown on single-crystal (001) Rh substrates. The BaTiO3 thin films exhibited strained tetragonal structures with c/a ratios of 1.05 (0.02 nm/pulse) and 1.03 (0.3 nm/pulse), depending on the film deposition rate. The increased tetragonality enhances the ferroelectric properties of the films. In addition, their deposition rate determines their leakage current and bandgap energy. Using scanning probe microscopy, we observed the surface morphologies and ferroelectric domain structures of the films. Furthermore, a ferroelectric domain analysis based on the Landau–Lifshitz–Kittel scaling law indicated that a reduction in the growth rate leads to an increase in the domain size and domain wall energy of BaTiO3 thin films. Finally, it was demonstrated that the optical bandgap of BaTiO3 thin films is related to their tetragonality.