Stress-tuning the bulk photovoltaic response in polycrystalline bismuth ferrite films

Abstract

Bulk or anomalous photovoltaic effect in ferroelectrics has recently sparked interest due to the generation of switchable photovoltages that are not limited by the bandgap of the material. The development of strategies to tune its magnitude is a key for the development of light-driven devices, e.g., photostrictive actuators, photostrictive sensors, or reconfigurable waveguides. In this paper, the bulk photovoltaic effect of polycrystalline solution-deposited bismuth ferrite thin films is studied under different stress conditions induced by different substrates and quantified using a direct strain assessment via x-ray diffraction. An increase in the short-circuit bulk photovoltaic current of 150% is observed with a change from a compressive stress of 0.54 GPa to a tensile stress of 0.93 GPa. This change is attributed to intrinsic piezophotovoltaic effect, demonstrating the potential to strain engineer the bulk photovoltaic effect in thin films.