Growth of epitaxial Mn and Zn codoped BiFeO3 thin films and an enhancement of photovoltage generated by a bulk photovoltaic effect

Recently, the bulk photovoltaic effect of BiFeO3 (BFO) thin films has attracted much attention because of its above bandgap photovoltage for realizing novel photovoltaic devices. In this study, the epitaxial growth of 1-mu m-thick Mn and Zn codoped BFO thin films has been demonstrated, and the effects of Mn and Zn codoping on the ferroelectric and bulk photovoltaic properties of the BFO thin films have been investigated. A 0.5% Mn and 0.5% Zn codoped BFO (BFMZO050) thin film on a SrRuO3-buffered vicinal-SrTiO3(001) substrate showed an atomically flat surface with a step-and-terrace structure, a low leakage current of 1.5 x 10(-6)A/cm(2) at 100 kV/cm, and well-saturated ferroelectric electric displacement-electric field (D-E) hysteresis loops. In addition, a Pt/BFMZO/Pt coplanar capacitor with an interelectrode distance of 260 mu m illuminated by a violet laser (lambda = 405 nm) showed an enhanced photovoltage of 145 V owing to the reduction in photoconductance by Mn and Zn codoping. (C) 2016 The Japan Society of Applied Physics