title: Toward Switchable Photovoltaic Effect via Tailoring Mobile Oxygen Vacancies in Perovskite Oxide Films.
abstract: The defect chemistry of perovskite oxides involves the cause to most of their abundant functional properties, including interface magnetism, charge transport, ionic exchange, and catalytic activity. The possibility to achieve dynamic control over oxygen anion vacancies offers a unique opportunity for the development of appealing switchable devices, which at present are commonly based on ferroelectric materials. Herein, we report the discovery of a switchable photovoltaic effect, that the sign of the open voltage and the short circuit current can be reversed by inverting the polarity of the applied field, upon electrically tailoring the distribution of oxygen vacancies in perovskite oxide films. This phenomenon is demonstrated in lateral photovoltaic devices based on both ferroelectric BiFeO3and paraelectric SrTiO3films, under a reversed applied field whose magnitude is much smaller than the coercivity value of BiFeO3. The migration of oxygen vacancies was directly observed by employing an advanced annular bright-field scanning transmission electron microscopy technique with in situ biasing equipment. We conclude that the band bending induced by the motion of oxygen vacancies is the driving force for the reversible switching between two photovoltaic states. The present work can provide an active path for the design of novel switchable photovoltaic devices with a wide range of transition metal oxides in terms of the ionic degrees of freedom.
authors.affiliation: Institute of Physics, Chinese Academy of Sciences , Beijing 100190, China.
authors.forename: Chen
authors.initials: C
authors.lastname: Ge
authors.affiliation: Institute of Physics, Chinese Academy of Sciences , Beijing 100190, China.|Collaborative Innovation Center of Quantum Matter , Beijing 100190, China.
authors.forename: Kui-Juan
authors.initials: KJ
authors.lastname: Jin
authors.affiliation: School of Materials Science and Engineering, State Key Lab of New Ceramics and Fine Processing, Tsinghua University , Beijing 100084, China.
authors.forename: Qing-Hua
authors.initials: QH
authors.lastname: Zhang
authors.affiliation: Institute of Physics, Chinese Academy of Sciences , Beijing 100190, China.|School of Science, China University of Geosciences , Beijing 100083, China.
authors.forename: Jian-Yu
authors.initials: JY
authors.lastname: Du
authors.affiliation: Institute of Physics, Chinese Academy of Sciences , Beijing 100190, China.|Collaborative Innovation Center of Quantum Matter , Beijing 100190, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Gu
authors.affiliation: Institute of Physics, Chinese Academy of Sciences , Beijing 100190, China.
authors.forename: Hai-Zhong
authors.initials: HZ
authors.lastname: Guo
authors.affiliation: Institute of Physics, Chinese Academy of Sciences , Beijing 100190, China.
authors.forename: Jing-Ting
authors.initials: JT
authors.lastname: Yang
authors.affiliation: Institute of Physics, Chinese Academy of Sciences , Beijing 100190, China.
authors.forename: Jun-Xing
authors.initials: JX
authors.lastname: Gu
authors.affiliation: Institute of Physics, Chinese Academy of Sciences , Beijing 100190, China.
authors.forename: Meng
authors.initials: M
authors.lastname: He
authors.affiliation: School of Science, China University of Geosciences , Beijing 100083, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Xing
authors.affiliation: Institute of Physics, Chinese Academy of Sciences , Beijing 100190, China.
authors.forename: Can
authors.initials: C
authors.lastname: Wang
authors.affiliation: Institute of Physics, Chinese Academy of Sciences , Beijing 100190, China.
authors.forename: Hui-Bin
authors.initials: HB
authors.lastname: Lu
authors.affiliation: Institute of Physics, Chinese Academy of Sciences , Beijing 100190, China.|Collaborative Innovation Center of Quantum Matter , Beijing 100190, China.
authors.forename: Guo-Zhen
authors.initials: GZ
authors.lastname: Yang
keywords: ion drift; laser molecular beam epitaxy; oxygen vacancy; perovskite oxide films; switchable photovoltaic effect