Nowadays, photovoltaic effect has been widely studied in various ferroelectric materials due to its applications as optoelectronic devices. In this work, with BiFeO₃ (BFO) films as the photovoltaic materials, we report the effects of Eu³⁺ doping content on the phase structure, ferroelectric and optical properties of BFO films grown on Ca_0.96Ce_0.04MnO₃/YAlO₃ (001) substrate. We found that a small doping level of 0.05 could induce a phase change of BFO from tetragonal to rhombohedral, due to the shrinking of the lattice upon Eu³⁺ doping and the breaking of surface terrace structure induced by Ca_0.96Ce_0.04MnO₃ layer. This results in a sharp band gap reduction from 3.30 eV to 2.60 eV, and a decrease in the coercivity of ferroelectric polarization switching. Based on these findings, we investigate the photovoltaic effects of ITO/Eu_xBi_1-xFeO₃/Ca_0.96Ce_0.04MnO₃ vertical capacitors. It is found that the short-circuit current density (J_sc) decreases with increasing Eu³⁺ doping, whereas the open-circuit voltage (V_oc) first increases to a level of 0.1 V and then decreases with further Eu³⁺ doping. This could be explained by the combined effect of Schottky-junction and depolarization field on the photovoltaic process. Our research suggests that a moderate Eu³⁺ doping is helpful for enhancing the photovoltaic effect of BFO thin film devices.

如今，光伏效应由于其作为光电器件的应用而在各种铁电材料中得到广泛研究。在这项工作中，以 BiFeO ₃ (BFO) 薄膜作为光伏材料，我们报告了 Eu ³⁺掺杂含量对在 Ca _0.96 Ce _0.04 MnO ₃ /YAlO ₃上生长的 BFO 薄膜的相结构、铁电和光学性能的影响（ 001) 基材。我们发现，由于 Eu ³⁺掺杂导致晶格收缩和 Ca _0.96 Ce _0.04 MnO引起的表面阶地结构破裂，0.05 的小掺杂水平可以诱导 BFO 从四方体到菱面体的相变₃层。这导致带隙从 3.30 eV 急剧减小到 2.60 eV，并且铁电极化转换的矫顽力降低。基于这些发现，我们研究了 ITO/Eu _x Bi _{1- x} FeO ₃ /Ca _0.96 Ce _0.04 MnO ₃垂直电容器的光伏效应。发现短路电流密度（J _sc）随着Eu ³⁺掺杂的增加而降低，而开路电压（V _oc）首先增加到0.1 V的水平，然后随着Eu ^{3+ 的}进一步增加而降低兴奋剂。这可以通过肖特基结和去极化场对光伏过程的综合影响来解释。我们的研究表明，适度的 Eu ³⁺掺杂有助于增强 BFO 薄膜器件的光伏效应。