Distinctive Photo-Induced Memory Effect in Heterostructure of 2D Van Der Waals Materials and Lanthanum Aluminate

The role of interface in atomically thin two-dimensional (2D) van der Waals materials is crucial in their novel optoelectronic properties. This study reports a mixed-dimensional optoelectronic memory device based on a heterostructure comprising 2D monolayer molybdenum disulfide and bulk lanthanum aluminate. The reversible photo-induced doping process accompanying persistent photocurrent phenomena is controlled using a gate voltage which is applied across the lanthanum aluminate dielectric substrate under light illumination. The extremely low gate electric field (<2 × 10³ V cm⁻¹) and the opposite gate voltage polarity compared with the general photo-doping cases indicate that the conventional band bending mechanism cannot be applied to this optoelectronic device. This distinctive photo-induced memory concept is validated in lanthanum aluminate-based heterostructures with other 2D materials such as graphene and tungsten diselenide. It is postulated that the heterostructure of atomically thin van der Waals materials that are in contact with various functional oxides provides a novel platform for next-generation optoelectronic devices.