Enhancing the heterointerface stability of Al₂O₃/Ba_0.5Sr_0.5TiO₃/Al₂O₃ composite thin films by adaptive anodizing method under high electric field

The utilization of multiple dielectric materials is an effective way to improve the energy storage performance of dielectric thin films. However, the heterointerfaces are the underbelly of multilayer dielectric thin films, which often causes defect-induced breakdown. The adaptive anodizing method was proposed to optimize dielectric heterointerface. The single anodization Al₂O₃/Ba_0.5Sr_0.5TiO₃/Al₂O₃ (SAB) thin films were fabricated by anodizing Al/Ba_0.5Sr_0.5TiO₃/Al thin films under the high electric field. The Al₂O₃/Ba_0.5Sr_0.5TiO₃ abrupt interfaces had been optimized to become more compact, forming stable transition heterointerfaces. The SAB thin films exhibit excellent electric properties, including a breakdown strength of 580 MV m⁻¹, an energy storage density of 16.4 J cm⁻³, and a leakage current density < 10^–6 A cm⁻² from 0 to 225 MV m⁻¹. The finite element simulation was constructed to demonstrate the defect self-repair process under high electric field. This work offers a promising strategy to fabricate multilayer dielectric thin films with high breakdown strength and energy storage density.