Emerging ferroelectric and antiferroelectric HfO-based thin films are attractive candidates for energy conversion and storage applications. In this work, the polar phase transformation between tetragonal and orthorhombic phases associated with ferroelectric or antiferroelectric behaviors is utilized to manipulate the electrocaloric cooling and energy storage performances in Zr-doped, woken up HfO ultrathin films. A giant electrocaloric temperature change of up to 11.85 K in HfZrO with the morphotropic phase boundary (MPB) state and a high energy storage density of 39.34 J/cm in the tetragonal phase-dominant HfZrO system are obtained. More interestingly, contrary to overdoping and excessive electric fields, an appropriate Zr concentration of 0.5 and an applicable driving field of 1.91 MV/cm are desired for the electrocaloric effect, resulting in an ultralow operating voltage as low as 1.3 V in this 6.8 nm thick HfZrO film. These findings illustrate that the structural design strategy is a visible method for achieving optimal energy-related behaviors and highlight the great possibilities for building future energy-related devices.

中文翻译：

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超低工作电压，实现 Hf1–xZrxO2 薄膜的能量转换性能


新兴的铁电和反铁电 HfO 基薄膜是能量转换和存储应用的有吸引力的候选者。在这项工作中，利用与铁电或反铁电行为相关的四方相和斜方相之间的极性相变来操纵 Zr 掺杂、唤醒 HfO 超薄膜的电热冷却和储能性能。在具有同形相界（MPB）态的 HfZrO 中获得了高达 11.85 K 的巨大电热温度变化，并且在以四方相为主的 HfZrO 体系中获得了 39.34 J/cm 的高能量存储密度。更有趣的是，与过度掺杂和过度电场相反，电热效应需要0.5的适当Zr浓度和1.91 MV/cm的适用驱动场，从而在6.8 nm厚的薄膜中实现低至1.3 V的超低工作电压HfZrO 薄膜。这些发现表明，结构设计策略是实现最佳能源相关行为的可见方法，并强调了构建未来能源相关设备的巨大可能性。