The conduction mechanism of large on/off ferroelectric diode currents in epitaxial (111) BiFeO₃ thin film

The large ferroelectric diode current modulated by bipolar polarization in epitaxial (111) BiFeO3 thin film has been observed. With the survey of different current leakage models, it is found that the space-charge limited current dominates the conduction. For the intrinsic physical understanding, the rectification of diode currents near domain coercive fields is attributed to gradient distribution of the trap charges between top and bottom electrode/ferroelectric interfaces, and the distributed charges can be reversed upon polarization reversal. Moreover, the retention time of the On and Off diode currents is over 104 s with their ratio of around 5:1.