Switchable photovoltaic response from polarization modulated interfaces in BiFeO3 thin films
Switchable photovoltaic response from polarization modulated interfaces in BiFeO3 thin films
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DOI：
10.1063/1.4870972
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发表时间：
2014-04-07
影响因子：
4
通讯作者：
Wang, Junling
中科院分区：
文献类型：
--
作者：
Fang, Liang;You, Lu;Wang, Junling
BiFeO₃薄膜电容器中的可切换光伏效应已被广泛研究。然而，光伏响应的起源仍存在争议。体退极化场和界面效应都被用于解释相关观测结果。在这项工作中，我们在SrTiO₃衬底上制备了以La₀.₇Sr₀.₃MnO₃和Pt为电极的BiFeO₃外延薄膜。与La₀.₇Sr₀.₃MnO₃/BiFeO₃/La₀.₇Sr₀.₃MnO₃相比，在Pt/BiFeO₃/La₀.₇Sr₀.₃MnO₃样品中可以观察到大得多的可切换光伏响应。此外，Pt/BiFeO₃/La₀.₇Sr₀.₃MnO₃样品的光伏电压几乎与La₀.₇Sr₀.₃MnO₃底部电极的厚度无关。我们认为，Pt/BiFeO₃界面处铁电极化对肖特基势垒的调制是光伏效应的主要原因，而体退极化场的贡献非常小。（C）2014美国物理联合会出版有限责任公司。
The switchable photovoltaic effect in BiFeO3 thin films capacitors has been studied extensively. However, the origin of the photovoltaic response is still under debate. Both bulk depolarization field and interface effects have been used to explain the observations. In this work, we fabricate BiFeO3 epitaxial films on SrTiO3 substrate with La0.7Sr0.3MnO3 and Pt as electrodes. Much larger switchable photovoltaic response can be observed in the Pt/BiFeO3/La0.7Sr0.3MnO3 samples, as compared with La0.7Sr0.3MnO3/BiFeO3/La0.7Sr0.3MnO3. Moreover, the photovoltaic voltage of the Pt/BiFeO3/La0.7Sr0.3MnO3 samples is nearly independent of the thickness of the La0.7Sr0.3MnO3 bottom electrode. We suggest that the Schottky barrier modulation by ferroelectric polarization at the Pt/BiFeO3 interface is mainly responsible for the photovoltaic effect, with very small contribution from the bulk depolarization field. (C) 2014 AIP Publishing LLC.