Conduction mechanism and switchable photovoltaic effect in (1 1 1) oriented BiFe0.95Mn0.05O3 thin film

Abstract

Epitaxial 200 nm BiFe0.95Mn0.05O3 (BFO) film was grown by pulsed laser deposition (PLD) on (1 1 1) oriented SrTiO3 substrate buffered with a 50 nm thick SrRuO3 electrode. The BFO thin film shows a rhombohedral structure and a large remnant polarization of Pr = 104 μC 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 (RT) and under 10 mW laser illumination, the as grown BFO film presents short-circuit current density (Jsc) and open circuit voltage (Voc) of 2.25 mA cm-2 and -0.55 V 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 -4.5 V (-225 kV cm-1) is observed which suggests a bulk non-centrosymmetric origin of the PV response.