Photovoltaic effect in rhombohedral and tetragonal phase BiFeO₃ ferroelectric thin films

Abstract:

The in-plane photovoltaic effect of epitaxially grown rhombohedral and tetragonal BiFeO₃ thin film were studied. The absorption spectrum of tetragonal BiFeO₃ is overall blue shifted compared with that of rhombohedral one, with an absorption onset near 2.5 eV and direct band gap of 3.1 eV. The photocurrent is measured with symmetric platinum electrodes in the plane to eliminate the interfacial energy barriers in rhombohedral and the effect of the depolarization field in tetragonal film. Except for the different sign and magnitude, the photo-current of both rhombohedral and tetragonal films depends on the linearly polarized light onto the plane of the sample along X and Y directions, showing evidence of a strong bulk photovoltaic effect (BPVE). These results indicate that the BPVE in both rhombohedral and tetragonal BiFeO₃ thin films could be further explored for the next generation of solar photovoltaic applications.

Keywords:

• Photovoltaic effect
• rhombohedral BiFeO3
• tetragonal BiFeO3
• photocurrent

5. Funding

The present work has been supported by the National Natural Science Foundation of China (Grant No. 51372283, 51402031, 61404018), the Natural Science Foundation Project of CQ(CSTC2018jcyjAX0416, CSTC2016jcyjA0175, CSTC2016jcyjA0349 ), the Commission of Science and Technology Research Young Project of CQ(KJQN201801509), the Foundation of Chongqing University of Science & Technology(CK2015B05, CK2015Z13), the Excellent Talent Project in University of Chongqing (Grant No. 2017-35), the Science and Technology Innovation Project of Social Undertakings and Peoples Livelihood Guarantee of Chongqing (Grant No. cstc2017shmsA0192), the Program for Innovation Teams in University of Chongqing, China (Grant No. CXTDX201601032), the Foundation of Chongqing University of Science & Technology (CK2015B05, CK2015Z13), the Latter Foundation Project of Chongqing University of Science & Technology (CKHQZZ2008002), the Scientific & Technological Achievements Foundation Project of Chongqing University of Science & Technology (CKKJCG2016328) and the cooperative project of academician workstation of Chongqing University of Science & Technology (CKYS2014Z01,CKYS2014Z03, CKYS2014Y04).