Achieving a high energy storage density in Ag(Nb,Ta)O 3 antiferroelectric films via nanograin engineering

作者：Hongbo Cheng, Xiao Zhai, Jun Ouyang, Limei Zheng, Nengneng Luo, Jinpeng LIU, Hanfei Zhu, Yingying WANG, Lanxia Hao, Kun Wang · 发表于：Journal of Advanced Ceramics · 年份：2022 · DOI：10.26599/jac.2023.9220678 · 被引用次数：33 · 研究领域：Ferroelectric and Piezoelectric Materials、Dielectric materials and actuators、Microwave Dielectric Ceramics Synthesis

Due to its lead-free composition and a unique double polarization hysteresis loop with a large maximum polarization ( P max ) and a small remnant polarization ( P r ), AgNbO 3 -based antiferroelectrics (AFEs) have attracted extensive research interest for electric energy storage applications. However, a low dielectric breakdown field ( E b ) limits an energy density and its further development. In this work, a highly efficient method was proposed to fabricate high-energy-density Ag(Nb,Ta)O 3 capacitor films on Si substrates, using a two-step process combining radio frequency (RF)-magnetron sputtering at 450 ℃ and post-deposition rapid thermal annealing (RTA). The RTA process at 700 ℃ led to sufficient crystallization of nanograins in the film, hindering their lateral growth by employing short annealing time of 5 min. The obtained Ag(Nb,Ta)O 3 films showed an average grain size ( D ) of ~14 nm (obtained by Debye–Scherrer formula) and a slender room temperature (RT) polarization–electric field ( P–E ) loop ( P r ≈ 3.8 μC·cm −2 and P max ≈ 38 μC·cm −2 under an electric field of ~3.3 MV·cm −1 ), the P–E loop corresponding to a high recoverable energy density ( W rec ) of ~46.4 J·cm −3 and an energy efficiency ( η ) of ~80.3%. Additionally, by analyzing temperature-dependent dielectric property of the film, a significant downshift of the diffused phase transition temperature ( T M2–M3 ) was revealed, which indicated the existence of a stable relaxor-like AFE phase...