Enhanced electric resistivity and dielectric energy storage by vacancy defect complex

• Main Authors: Pan, Hao, Feng, Nan, Xu, Xing, Li, Weiwei, Zhang, Qinghua, Lan, Shun, Liu, Yi-Qian, Sha, Haozhi, Bi, Ke, Xu, Ben, Ma, Jing, Gu, Lin, Yu, Rong, Shen, Yang, Wang, Renshaw Xiao, MacManus-Driscoll, Judith L., Chen, Chong-Lin, Nan, Ce-Wen, Lin, Yuan-Hua
• Other Authors: School of Physical and Mathematical Sciences
• Format: Article
• Language: English
• Published: 2022
• Subjects: Science::Physics; Dielectric Energy Storage; Defect
• Online Access: https://hdl.handle.net/10356/156689
• Institution: Nanyang Technological University

The presence of uncontrolled defects is a longstanding challenge for achieving high electric resistivity and high energy storage density in dielectric capacitors. In this study, opposite to conventional strategies to suppress de- fects, a new approach, i.e. , constructing defects with deeper energy levels, is demonstrated to address the inferior resistivity of BiFeO 3 -based dielectric films. Deep-level vacancy complexes with high charge carrier activation energies are realized via deliberate incorporation of oxygen vacancies and bismuth vacancies in low-oxygen- pressure deposited films. This method dramatically increases the resistivity by ∼4 orders of magnitude and the breakdown strength by ∼150%, leading to a ∼460% enhancement of energy density (from 14 to 79 J cm − 3 ), as well as improved efficiency and performance reliability. This work reveals the significance of rational design and precise control of defects for high-performance dielectric energy storage. The deep-level vacancy complex approach is generalizable to wide ranges of dielectric systems and functional applications.