Real-time observation of dynamic process of oxygen vacancy migration in cerium oxides under electric field

• Published in: Applied physics letters Vol. 107; no. 21
• Main Authors: Li, Xiaomin, Qi, Kuo, Sun, Muhua, Huang, Qianming, Xu, Zhi, Wang, Wenlong, Bai, Xuedong
• Format: Journal Article
• Language: English
• Published: Melville American Institute of Physics 23-11-2015
• Subjects: ANODES; Applied physics; CERIUM OXIDES; CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ELECTRIC FIELDS; ELECTRIC POTENTIAL; Gas sensors; INTERFACES; Migration; OXYGEN; Random access memory; Scale (corrosion); THIN FILMS; TRANSMISSION ELECTRON MICROSCOPY; VACANCIES
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.4936333

The dynamic process of oxygen vacancy migration driven by the external electric field is directly observed at atomic scale in the cerium oxides (CeO2) thin film by in-situ transmission electron microscopy method. When a bias voltage of a proper value is applied across the CeO2 film, the oxygen vacancies are formed near the interface of CeO2/anode, followed by their migration along the direction of the external electric field. The structural modulation occurs in the [110] zone axis due to the ordering of oxygen vacancies. The migration of oxygen vacancies results in the reversible structural transformation, i.e., releasing and storing oxygen processes in CeO2, which is of great significance for the ionic and electronic applications of the cerium oxides materials, such as oxygen pump, gas sensor, resistive random access memory, etc.