Reconfigurable optical memory based on MoS2/QDs mixed-dimensional van der Waals heterostructure

Abstract

Optical memory unit with the ability to detect and store optical signals is increasingly becoming a crucial part of advanced data communication and image sensing technology. Despite great efforts devoted to develop high-performance optical memory devices based on two-dimensional (2D) material, the photoelectric conversion is still limited to defect-dominant photo-generated carrier trapping/de-trapping process at the interface of 2D materials. Here, a reconfigurable optical memory implanted with photonic programming/electric erasing operation is demonstrated based on MoS2/quantum dots (QDs) mixed-dimensional heterostructure. Unique photoelectric coupling effect between MoS2 and QDs leads to a continuous n-doping on MoS2 channel after light exposure removed, resulting in the generation of persistent photocurrent. Excellent optical memory characteristics such as high programming/erasing ratio, long retention time and stable operation cycles have been achieved and demonstrated to be gate-tunable. Besides, multi-level optical data storage with ten different states is also realized by applying a series of programmable optical signals. Owing to the unique dynamic response of mix-dimensional van der Waals heterostructure to optical and electric signals, our proposed optical memory transistor may pave up a new path to explore photoelectric conversion in low-dimensional system and develop high-performance optoelectronics for a broad range of applications.