Boosting the energy storage performance of BCZT-based capacitors by constructing a Schottky contact†

Abstract

Multilayer thin films composed of dielectric Ba_0.7Ca_0.3Zr_0.2Ti_0.8O₃ (BCZT) and oxygen-deficient BCZT (BCZT-OD) were fabricated on (001)-oriented NSTO substrates using the pulsed laser deposition (PLD) technique. Unlike conventional approaches to energy storage capacitors, which primarily focus on compositional or structural modifications, this study explored the influence of the layer sequence and periodicity. The interface between the NSTO substrate and the BCZT-OD layer forms a Schottky barrier, resulting in electric field redistribution across the sublayers of the BCZT/BCZT-OD//(1P) thin film. This redistribution delays the breakdown of the BCZT layer, significantly enhancing the film's electric breakdown strength. Furthermore, mathematical analysis reveals that the electric field redistribution amplifies dipole polarization, with BCZT-OD-initiated multilayers exhibiting superior polarization compared to those with equivalent periodicity but different starting layers. Consequently, the BCZT/BCZT-OD//(1P) multilayer achieves an exceptional recoverable energy density (W_rec) of 150.22 J cm⁻³ and an energy efficiency (η) of 83.07%, surpassing typical performance benchmarks for BCZT-based thin films. These findings are corroborated by comprehensive structural characterization studies, performance evaluations, and finite element simulations, which further validate the role of the Schottky barrier in enhancing voltage endurance. Analogous to “Tian Ji's Strategy for Horse Racing”, this work achieved high W_rec by sacrificing the ferroelectricity of the negative side of the P–E loop, introducing an innovative paradigm for designing and developing next-generation electronic devices.