Reduced leakage current and enhanced energy storage performance of BZNT/BTO multilayer structures: Implications in electronic devices

Abstract

The extremely high recoverable energy density (Wrec) and efficiency (η) of lead-free thin films make them a promising candidate for application in miniature power devices. Here, a stable design of multilayered structures of BaTiO3 (BTO) and Bi[Zn2/3(Nb0.85Ta0.15)1/3]O3 (BZNT) have been fabricated using the pulsed laser deposition (PLD) technique on n-type Si, and Pt/Ti/SiO2/Si (Pt-Si) substrates. The effect of a number of stacking of alternate BTO and BZNT layers on the structural, microstructural, electrical, and ferroelectric properties is investigated. The films exhibited a polycrystalline nature, and the tetra-layer stacked film (BZNT/BTO3) exhibited better crystallinity, improvement in microstructure, and grain growth than that of the bi-layer stacked film (BZNT/BTO1). The improvement in ferroelectric response in the tetra-layer film is well correlated to the low leakage current density (∼10-7 A/cm2 at ±500 kV/cm) owing to reduced defects in the film. The reduced oxygen vacancies and dielectric loss tangent of order 10-3 validate the high quality of BZNT/BTO3 film exhibiting a large Wrec of 52.19 J/cm3 and high energy efficiency of 92.21 % achieved through interface engineering. These findings demonstrate the promising future for BTO-based multilayer thin film in high-power and energy-storage device applications.