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

TL;DR

This study maps the photovoltaic response in BiFeO3 single crystals, revealing how a unique 180° ferroelectric domain wall influences local photocurrent through internal field distortions, but not as a direct photoelectric center.

Contribution

It demonstrates the impact of a specific ferroelectric domain wall on photovoltaic response and clarifies that the effect arises from internal field distribution rather than the domain wall itself.

Findings

Photocurrent maps are affected by the domain wall's presence and shape.

No extra photocurrent is observed when illuminating directly on the domain wall.

Internal electric fields influenced by domain wall charge explain the observed effects.

Abstract

Using an experimental setup designed to scan a submicron sized light spot and collect the photogenerated current through larger electrodes, we map the photovoltaic response in ferroelectric BiFeO3 single crystals. We study the effect produced by a unique 180{\textdegree} ferroelectric domain wall (DW) and show that the photocurrent maps are significantly affected by its presence and shape. The effect is large in its vicinity and in the Schottky barriers at the interface with the Au electrodes, but no extra photocurrent is observed when the illuminating spot touches the DW, indicating that this particular entity is not the heart of specific photo-electric properties. Using 3D modelling, we argue that the measured effect is due to the spatial distribution of internal fields which are significantly affected by the charge of the DW due to its distortion.