Engineering of Grain Boundary in Pb(Zr0.52Ti0.48)O3 Epitaxial Films for Tunable Piezoelectric Properties

Grain engineering has long been utilized to modify the electrical poling behavior of piezoelectric ceramics. In this study, we explore the impact of grain boundary engineering on the piezoelectric performance of Pb(Zr0.52Ti0.48)O3 (PZT) epitaxial films. By precisely tuning growth parameters, we produce dense and “rod-like” grain boundary PZT films. These “rod-like” PZT films exhibit a markedly different piezoelectric response compared to dense epitaxial PZT films that are free of grain boundaries. When subjected to 5 N external pressure at 190 °C, the output voltage of the dense PZT film reaches 17.7 mV, while the “rod-like” PZT film’s output drops to 5.6 mV, highlighting the attenuating influence of grain boundaries on piezoelectricity. Both films demonstrate an increasing piezoelectric response with rising temperatures, suggesting a pyro-piezoelectric effect in PZT. Additionally, both films show excellent durability, maintaining performance over 1000 cycles. Piezoelectric force microscopy analysis reveals that grain boundaries hinder reversible domain wall motion, leading to reduced piezoelectric coefficients in the PZT films. This study underscores the critical role of grain boundaries in influencing the piezoelectric behavior of epitaxial films and offers insights for grain boundary engineering in the development of self-sustained, smart sensing applications.