Enhancement of Oxygen Vacancies Induced Photovoltaic Effects in Bi sub(0.9)La sub(0.1)FeO sub(3) Thin Films

The photovoltaic effect in Ag/Bi sub(0.9)La sub(0.1)FeO sub(3)/La sub(0.7)Sr sub(0.3)MnO sub(3) heterostructures was investigated and the short circuit photocurrent was found to be strongly dependent on the polarization orientation and oxygen vacancies (V sub(Os)) distribution. The photocurrent direction was switched accompanying polarization switching. Besides, according to manipulate the V sub(Os) accumulated at either the Ag/Bi sub(0.9)La sub(0.1)FeO sub(3) or the Bi sub(0.9)La sub(0.1)FeO sub(3)/La sub(0.7)Sr sub(0.3)MnO sub(3) interface by electric pulses, obvious enhancement of photovoltaic effects was obtained. These results can be explained well using the concepts of drift current and diffusion current controlled by the combination of oxygen vacancies and polarization. This work provides deep insights into the nature of photovoltaic effects in ferroelectric films, and will facilitate the advanced design devices combining spintronic, electronic, and optical functionalities.