Structure and properties of lead zirconate titanate thin films by pulsed laser deposition

Abstract

Lead zirconate titanate (PZT) thin films with different microstructure were prepared and the relationships between the microstructure and physical properties were investigated. Epitaxial growth process of the PZT films on SrTiO3 (STO) substrates by pulsed laser deposition (PLD) method was also studied, in which a two-layer structure at early growth stage was discovered, and column growth mode was observed with increased film thickness. With our developed LSMO/YBCO/YSZ intermediate layers, another pseudo epitaxial PZT film was achieved on silicon substrate. The pseudo epitaxial PZT film was characterized with granular and porous morphology, but exhibited significantly enhanced ferroelectric polarization. Our results have shown that improving the epitaxial quality without considering the tensile stress effects may not be sufficient for achieving the optimal ferroelectric properties for a ferroelectric film on silicon substrate. Although PZT films with dense microstructure would lead to a significantly higher dielectric constant and remnant polarization, but a less dense film could have a substantially higher piezoelectric voltage constant due to its low dielectric constant. These understandings on the relationship between the microstructure and properties are essential to tailor the microstructure and thus the performance of the PZT films aiming at different applications.