Non-volatile optical memory in vertical van der Waals heterostructures

Emulating synaptic plasticity in an artificial neural network is crucial to mimic the basic functions of the human brain.In this work, we report a new optoelectronic resistive random access memory(ORRAM) in a three-layer vertical heterostructure of graphene/Cd Se quantum dots(QDs)/graphene, which shows non-volatile multi-level optical memory under optical stimuli,giving rise to light-tunable synaptic behaviors. The optical non-volatile storage time is up to ～450 s. The device realizes the function of multi-level optical storage through the interlayer changes between graphene and QDs. This work highlights the feasibility for applying two-dimensional(2D) materials in ORRAM and optoelectronic synaptic devices towards artificial vision.