Conduction mechanism and switchable photovoltaic effect in (111) oriented BiFe$_{0.95}$Mn$_{0.05}$O$_{3}$ thin film

Abstract

Epitaxial 200nm BiFe$_{0.95}$Mn$_{0.05}$O$_{3}$ (BFO) film was grown by pulsed laser deposition on (111) oriented SrTiO3 substrate buffered with a 50nm thick SrRuO$_{3}$ electrode. The BFO thin film shows a rhombohedral structure and a large remnant polarization of Pr = 104 $\mu$C/cm$^{2}$. By comparing I(V) characteristics with different conduction models we reveal the presence of both bulk limited Poole-Frenkel and Schottky interface mechanisms and each one dominates in a specific range of temperature. At room temperature and under 10mW laser illumination, the as grown BFO film presents short-circuit current density (Jsc) and open circuit voltage (Voc) of 2.25mA/cm$^{2}$ and -0.55V respectively. This PV effect can be switched by applying positive voltage pulses higher than the coercive field. For low temperatures a large Voc value of about -4.5V (-225kV/cm) is observed which suggests a bulk non-centrosymmetric origin of the PV response.