Unveiling the Anomalous Photovoltaic Effect of Ferroelectric Domain Walls in BiFeO3 Thin Films
Unveiling the Anomalous Photovoltaic Effect of Ferroelectric Domain Walls in BiFeO3 Thin Films
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DOI：
10.1103/physrevapplied.19.024050
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发表时间：
2023-02-17
影响因子：
4.6
通讯作者：
Sun, Lin
中科院分区：
文献类型：
--
作者：
Lin, Jianjun;Chen, Yuang;Sun, Lin
铁电畴壁（DWs）的存在可以使铁电光伏器件产生带隙以上的光电压，这就是异常光伏效应（APV），其机制仍在争论中。本文通过定量分析BiFeO3薄膜中非周期DWs和周期条形DWs的光偏振角依赖性光伏效应，报道了71°DWs下的有效电场和局部体光伏（BPV）分量。在白光照射下的光伏测量直接揭示了条纹DWs处电场的显著增强。条纹DWs的BPV效应约为域的25倍。此外，缺陷态可能会使光生载流子重新组合，从而大大削弱光生载流子的电场，而它们对BPV效应的影响可以忽略不计。这项工作为铁电DWs中APV效应的机制提供了更深入的了解。
The presence of ferroelectric domain walls (DWs) can generate an above-band-gap photovoltage of a ferroelectric photovoltaic device, which is the anomalous photovoltaic (APV) effect, and its mechanism is still under debate. Here, the effective electric field and the local bulk photovoltaic (BPV) component at 71 degrees DWs are reported by quantitatively analyzing the light polarization angle-dependent photovoltaic effect of nonperiodic DWs and periodic stripe DWs in BiFeO3 films. The photovoltaic measurement under white light illumination directly reveals a significantly enhanced electric field at stripe DWs in comparison with the domains. The BPV effect at stripe DWs is about 25 times as large as that of the domains. Furthermore, the defect states at the DWs may recombine the photogenerated carriers and drastically weaken the electric field of the DWs, whereas they negligibly mitigate the BPV effect. This work offers a deeper insight into the mechanism of the APV effect at ferroelectric DWs.