Graphene Dynamic Synapse with Modulatable Plasticity

Abstract

The synaptic activities in nervous system is the basis of memory and learning behaviours, and the concept of biological synapses also spurred the development of neuromorphic engineering. In recent years, the hardware implementation of biological synapse has been achieved based on CMOS circuits, resistive switching memory and field effect transistors with ionic dielectrics. However, the artificial synapse with regulatable plasticity has never been realized in device level. Here, an artificial dynamic synapse based on twisted bilayer graphene is demonstrated with tunable plasticity. Due to the ambipolar conductance of graphene, both behaviours of the excitatory synapse and the inhibitory synapse could be realized in a single device. Moreover, the synaptic plasticity could also be modulated by tuning the carrier density of graphene. Since the artificial synapse here could be regulated and inverted via changing the bottom gate voltage, the whole process of synapse development could be imitated. Hence, this work would offer a broad new vista for the 2D material electronics, and guide the innovation of neuro-electronics fundamentally.