Observation of Chargeable Photoconductivity in Bi0.85La0.15FeO3/Q2DEG-Based Multiferroic Heterostructure
Chargeable photoconductivity, a non-volatile photoresponse phenomenon, was investigated in multiferroic heterostructures comprising Bi0.85La0.15FeO3 (BLFO) and a quasi-two-dimensional electron gas (Q2DEG). Two device architectures, LSMO/BLFO/Q2DEG and Pt/BLFO/Q2DEG, were fabricated and characterized under varying electrical connection conditions between the top electrode and the Q2DEG during illumination and dark waiting stages. Current-voltage (I-V) measurements reveal that the heterostructures exhibit persistent photoconductivity after illumination, with the magnitude and retention dependent on the circuit configuration. Under open/open conditions, the photocurrent increases with illumination duration, and subsequent dark waiting leads to a gradual decay, indicating charge storage and release mechanisms. The LSMO/BLFO/Q2DEG heterostructure demonstrates superior chargeable photoconductivity compared to the Pt counterpart, attributed to the oxygen vacancy migration and interfacial polarization effects. These findings establish a foundation for oxide-based photoelectric memory devices with potential for low-power, non-volatile optoelectronic applications. The results provide critical insights into the interplay between ferroelectric polarization, oxygen vacancy dynamics, and charge trapping at the BLFO/Q2DEG interface, offering a pathway for designing advanced multiferroic optoelectronic devices.