Photovoltaic response around a unique180{ extdegree} ferroelectric domain wall in single crystalline BiFeO3

摘要

Using an experimental setup designed to scan a submicron sized light spot andcollect the photogenerated current through larger electrodes, we map thephotovoltaic response in ferroelectric BiFeO3 single crystals. We study theeffect produced by a unique 180{\textdegree} ferroelectric domain wall (DW) andshow that the photocurrent maps are significantly affected by its presence andshape. The effect is large in its vicinity and in the Schottky barriers at theinterface with the Au electrodes, but no extra photocurrent is observed whenthe illuminating spot touches the DW, indicating that this particular entity isnot the heart of specific photo-electric properties. Using 3D modelling, weargue that the measured effect is due to the spatial distribution of internalfields which are significantly affected by the charge of the DW due to itsdistortion.