Heterogeneous Layer Configuration Engineering for Enhanced Piezoelectric Performance of Bi(Fe0.95Mn0.03Ti0.02)O3/Bi0.5Na0.5TiO3-0.06BaTiO3 Composite Thin Films

Abstract

With the rapid development of smart electronics and micro-electro-mechanical systems (MEMS), lead-free piezoelectric thin films with both high piezoelectric activity and environmental stability have emerged as core materials, directly determining the performance upper limits of next-generation miniaturized devices. Heterostructured Bi(Fe_0.95Mn_0.03Ti_0.02)O₃/Bi_0.5Na_0.5TiO₃-0.06BaTiO₃ (denoted as B and A) multilayer thin films with distinct stacking sequences (BAA, ABA, AAB) were fabricated. The BAA structure exhibits superior performance, showing a high piezoelectric coefficient (d₃₃^⁎) of 98.1 pm/V—approximately 4.2 times that of the pure A thin film—along with a maximum polarization of 56.2 μC/cm² and a dielectric constant of 480 at 1 kHz. Moreover, the leakage current density is reduced by two orders of magnitude, and robust thermal stability of polarization is maintained over the temperature range of 25 - 200 °C. This work clarifies the mechanism by which heterolayer structure enhances piezoelectric properties, provides a strategy for developing high-performance lead-free piezoelectric thin films, and promotes their application in microelectronic devices, thereby driving technological and industrial progress in the field.