Machado Pamela, Salles Pol, Frebel Alexander, De Luca Gabriele, Ros Eloi, Hagendorf Christian, Fina Ignasi, Puigdollers Joaquim, Coll Mariona
Institut de Ciència de Materials de Barcelona, ICMAB-CSIC, Campus UAB, Bellaterra 08193, Spain.
Department of Materials and Geo Sciences, Surface Science Division, Technische Universität Darmstadt, Jovanka-Bontschits-Straße 2, D-64287 Darmstadt, Germany.
ACS Appl Electron Mater. 2024 Nov 13;6(11):8251-8259. doi: 10.1021/acsaelm.4c01533. eCollection 2024 Nov 26.
Photoferroelectric BiFeO (BFO) has attracted renewed interest to be integrated into thin film photovoltaic (PV) devices as a stable, lead-free, and versatile photoabsorber with simplified architecture. While significant efforts have been dedicated toward the exploration of strategies to tailor the properties of this photoabsorber to improve the device performance, efficiencies still remain low. The modification of the BFO interface by the incorporation of transport-selective layers can offer fresh opportunities to modify the properties of the device. Identifying an optical and electrically suitable selective layer while ensuring easy device processing and controlled film properties is challenging. In this work, we determine the influence of incorporating a ZnO layer on the ferroelectric and photoresponse behavior of an epitaxial BiFeCoO (BFCO)-based heterostructure. The device is completed with Sn-doped InO (ITO) and LaSrMnO (LSMO) electrodes. This all-oxide system is stable under ambient conditions and displays robust ferroelectricity. The coupled ferroelectricity-photoresponse measurements demonstrate that the short circuit current can be modulated by ferroelectric polarization in up to 68% under blue monochromatic light. Also, the responsivity of the system with the ZnO-modified interface is larger than that of the system with no ZnO. Complementary band energy alignment studies reveal that the observed increase in the short circuit current density of the device with ZnO is attributed to lower Fermi level energy at the ZnO/BFCO interface compared to the ITO/BFCO interface, which reduces charge recombination. Therefore, this study provides useful insights into the role of the ZnO interface layer in stable BFO-based devices to further explore their viability for potential optoelectronic applications.
光铁电体BiFeO（BFO）作为一种结构简化的稳定、无铅且通用的光吸收体，已重新引起人们将其集成到薄膜光伏（PV）器件中的兴趣。尽管人们付出了巨大努力来探索调整这种光吸收体性能以提高器件性能的策略，但效率仍然很低。通过引入传输选择性层来修饰BFO界面，可以为改变器件性能提供新的机会。在确保易于器件加工和可控薄膜性能的同时，确定光学和电学上合适的选择性层具有挑战性。在这项工作中，我们确定了引入ZnO层对基于外延BiFeCoO（BFCO）的异质结构的铁电和光响应行为的影响。该器件由掺锡的InO（ITO）和LaSrMnO（LSMO）电极制成。这种全氧化物系统在环境条件下稳定，并显示出强大的铁电性。铁电-光响应耦合测量表明，在蓝色单色光下，短路电流可被铁电极化调制高达68%。此外，具有ZnO修饰界面的系统的响应度大于没有ZnO的系统。互补带能量对准研究表明，观察到的含ZnO器件短路电流密度的增加归因于与ITO/BFCO界面相比，ZnO/BFCO界面处较低的费米能级能量，这减少了电荷复合。因此，本研究为ZnO界面层在基于BFO的稳定器件中的作用提供了有用的见解，以进一步探索其在潜在光电子应用中的可行性。
