Reversible charge injection in artificially created charged domain wall region

The impact of electric field application in the charged domain wall (DW) region on the performance of DW devices remains elusive. Here, we present our observations of substantial charge injection occurring in an artificially created charged DW region. Rapid charge injection coincides with polarization switching, contributing to the transient current collected for the integration of polarization-voltage hysteresis loops. Subsequently, a gradual injection of charges persists under externally applied voltages, diffusing into the thin film from the DW region to screen the space defect dipoles and effectively suppressing the imprint field. The process of charge injection proves reversible and is notably more pronounced in aged ferroelectric thin films, as evidenced in planar BiFeO3 nanodevices where the charge injection amount is five orders of magnitude higher than charges generated from polarization switching. This work constitutes a significant contribution to understanding the intricate process of charge injection and its influence on charged DW.