Huang Qianwei, Chen Zibin, Cabral Matthew J, Wang Feifei, Zhang Shujun, Li Fei, Li Yulan, Ringer Simon P, Luo Haosu, Mai Yiu-Wing, Liao Xiaozhou
School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, NSW, Australia.
Key Laboratory of Optoelectronic Material and Device, Department of Physics, Shanghai Normal University, Shanghai, China.
Nat Commun. 2021 Apr 7;12(1):2095. doi: 10.1038/s41467-021-22355-1.
Failure of polarization reversal, i.e., ferroelectric degradation, induced by cyclic electric loadings in ferroelectric materials, has been a long-standing challenge that negatively impacts the application of ferroelectrics in devices where reliability is critical. It is generally believed that space charges or injected charges dominate the ferroelectric degradation. However, the physics behind the phenomenon remains unclear. Here, using in-situ biasing transmission electron microscopy, we discover change of charge distribution in thin ferroelectrics during cyclic electric loadings. Charge accumulation at domain walls is the main reason of the formation of c domains, which are less responsive to the applied electric field. The rapid growth of the frozen c domains leads to the ferroelectric degradation. This finding gives insights into the nature of ferroelectric degradation in nanodevices, and reveals the role of the injected charges in polarization reversal.
铁电材料中由循环电负载引起的极化反转失败，即铁电降解，一直是一个长期存在的挑战，对铁电体在可靠性至关重要的器件中的应用产生负面影响。人们普遍认为空间电荷或注入电荷主导了铁电降解。然而，该现象背后的物理机制仍不清楚。在这里，我们使用原位偏置透射电子显微镜，发现在循环电负载过程中薄铁电体中电荷分布的变化。畴壁处的电荷积累是形成c畴的主要原因，c畴对外加电场的响应较小。冻结c畴的快速生长导致铁电降解。这一发现深入了解了纳米器件中铁电降解的本质，并揭示了注入电荷在极化反转中的作用。
