Optimized energy storage performance in HZO3ZO12 thin films through modulation of deposition temperature and film thickness

Abstract

Dielectric capacitors are critical for energy storage applications, especially in pulsed power systems, owing to their ultrahigh power density and ultrafast charge/discharge capabilities. Among them, HfO₂-based thin films are particularly promising for micro-energy storage devices. In this work, double-layered Hf₀.₅Zr₀.₅O₂(3 nm)/ZrO₂(12 nm) (HZO3ZO12) films are deposited across a wide temperature range (80–225 °C) to systematically investigate their energy storage performance. A machine learning-assisted multi-objective optimization approach is employed to identify the optimal deposition temperature, revealing 128 °C as the ideal condition for maximizing energy storage properties. Further thickness optimization based on this deposition temperature is used to enhance the performance, achieving an excellent energy storage density of 113 J/cm³ at an applied electric field of 9.1 MV/cm. This study demonstrates a powerful strategy combining machine learning with experimental design to optimize dielectric capacitors, providing a roadmap for developing high-performance energy storage materials.