Graphene Dynamic Synapse with Modulatable Plasticity

Abstract

The synaptic activities in the nervous system is the basis of memory and learning behaviors, and the concept of biological synapse has also spurred the development of neuromorphic engineering. In recent years, the hardware implementation of the 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 of the 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 behaviors 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. Because 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.

Photonic Potentiation and Electric Habituation in Ultrathin Memristive Synapses Based on Monolayer MoS2

“…And a memory cell based on a vertically stacked monolayer MoS 2 /h‐BN/monolayer graphene heterostructure was demonstrated by Vu et al Furthermore, Zhou and co‐workers observed nonvolatile charge‐trap memory in MoS 2 and WSe 2 layers with 3D charge‐trap gate stack . At the same time, artificial synapses based on multilayer 2D materials were also realized in twisted bilayer graphene and multilayer MoS 2 . However, to the best of our knowledge, an ultrathin memristive synapse based on monolayer 2D materials has yet to be realized.…”

2D Layered Materials for Memristive and Neuromorphic Applications

“…Similar behavior of restricting lateral growth of filaments has been also reported in Au/(PEA) 2 PbBr 4 /Gr vertical structure. [64] Copyright 2015, American Chemical Society Publishing. At this current level, basic behaviors of synapse plasticity including EPSC, IPSC, STP, and LTP have been demonstrated.…”

“…Memristive devices relying on charge-trapping effect [64][65][66][67][68][69][70] at the interface are not suitable for development of robust devices, as it is difficult to control the trapping/detrapping process in a reliable way. The unique physical properties that 2D layered materials and vdW heterostructure possess have not been fully exploited for designing neuromorphic devices with new working principles.…”

Recent Progress in Synaptic Devices Based on 2D Materials

“…The number of reports on 2D materials‐based synaptic devices has accordingly increased rapidly. The most representative 2D materials in the aforementioned are graphene, transition metal dichalcogenides (TMDs) (e.g., MoS 2 and WSe 2 ), black phosphorus (BP), hexagonal boron nitride (h‐BN), and various vdW heterostructures with these 2D materials …”