Mechanism of switchable and nonswitchable short-circuit photocurrent accompanying polarization switching in Bi_(0.9)La_(0.1)FeO_3 thin films

摘要

The short-circuit photocurrent (I_(sc)) of Bi_(0.9)La_(0.1)FeO_3 epitaxial thin films has been investigated. Switchable and nonswitchable Isc accompanying polarization switching was observed and it can be explained well using the concepts of drift current and diffusion current controlled by the combination of oxygen vacancies, polarization and conductive domain wall. The sign of photocurrent is independent of the polarization direction when the modulation of photocurrent induced by oxygen vacancies or conductive domain walls is large enough to offset that induced by polarization. Our work provides a deep insight into the nature of photovoltaic effects in ferroelectric films, and will facilitate the advanced design of switchable devices combining spintronic, electronic, and optical functionalities.