Achieving high microscale photoconductivity in Gd-modified bismuth ferrite via modulating ferroelectric polarization

Abstract

This work demonstrates the critical role of ferroelectric polarization in determining the two-dimensional photoconduction properties of 7 mol% Gd-modified bismuth ferrite (BiFeO₃, BFO) ceramics under 405 nm-wavelength illumination. A significant enhancement in photocurrent upon external electric field poling is correlated with adjustment in the internal electric field induced by ferroelectric polarization, which boosts the charge mobility via tilting the energy-band structure. The enhanced photoconduction is linked to the domain reorientation and increased domain walls. The evolution plays a critical role in the electric field-enhanced photocurrent since domain walls serve as conductive transport networks for charge flow. Furthermore, a sequential increase in photocurrent with increasing illumination intensity can be attributed to an increased number of photo-generated charge carriers. This study uncovers the vital effects of ferroelectric polarization on the photoelectric properties of BFO-based materials, thus providing essential insight for optoelectronic applications.