Protonation‐Driven Polarization Retention Failure in Nano‐Columnar Lead‐Free Ferroelectric Thin Films
Year: 2024
Type: article
Abstract: Understanding microscopic mechanisms of polarization retention characteristics in ferroelectric thin films is of great significance for exploring unusual physical phenomena inaccessible in the bulk counterparts and for realizing thin‐film‐based functional electronic devices. Perovskite (K,Na)NbO 3 is an excellent class of lead‐free ferroelectric oxides attracting tremendous interest thanks to its potential applications to nonvolatile memory and eco‐friendly energy harvester/storage. Nonetheless, in‐depth investigation of ferroelectric properties of (K,Na)NbO 3 films and the following developments of nano‐devices are limited due to challenging thin‐film fabrication associated with nonstoichiometry by volatile K and Na atoms. Herein, ferroelectric (K,Na)NbO 3 films of which the atomic‐level geometrical structures strongly depend on thickness‐dependent strain relaxation are epitaxially grown. Nanopillar crystal structures are identified in fully relaxed (K,Na)NbO 3 films to the bulk states representing a continuous reduction of switchable polarization under air environments, that is, polarization retention failures. Protonation by water dissociation is responsible for the humidity‐induced retention loss in nano‐columnar (K,Na)NbO 3 films. The protonation‐driven polarization retention failure originates from domain wall pinning by the accumulation of mobile hydrogen ions at charged domain walls for effective screening of polarization‐bound charges. Conceptually, the results will be utilized for rational design to advanced energy materials such as photo‐catalysts enabling ferroelectric tuning of water splitting.
Source: Advanced Science
Authors: Muhammad Sheeraz, Chang Won Ahn, Nguyen Xuan Duong, Soo‐Yoon Hwang, Ji‐Soo Jang, Eun‐Young Kim, Yoon Ki Kim, Jaeyeong Lee, Jong Sung Jin, Jong‐Seong Bae, Myang Hwan Lee, Hyoung‐Su Han, Gi‐Yeop Kim, Shinuk Cho, Tae Kwon Song, Sang Mo Yang, Sang Don Bu, Seung‐Hyub Baek, Si‐Young Choi, Ill Won Kim, Tae Heon Kim
Institutions: University of Ulsan, Pohang University of Science and Technology, Korea Institute of Science and Technology, Jeonbuk National University, Sogang University, Korea Basic Science Institute, Changwon National University, Korea University of Science and Technology, Institute for Basic Science
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $6,120
OpenAlex ID: W4404016142