Figure 6.

2D-Based Electronic Synapses

(A) Schematic representation of a biological synapse.

(B) Synaptic device realized by a 2-terminal memristor device with 2D WS₂ as the switching medium in a Pd/WS₂/Pt stack. Reprinted with permission from (Yan et al., 2019b). Copyright 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

(C) Multiple conductance states corresponding to the synaptic weight states exhibited by the Ni/MoS₂/graphene synapse under DC bias with the lowest programming current of 1 nA. Reprinted with permission from (Krishnaprasad et al., 2019). Copyright 2019 AIP Publishing.

(D) Robustness of the 2D memristors with active MoS₂ medium and graphene electrodes showing sustained switching between HRS and LRS for 10⁷ cycles. Reprinted with permission from (Wang et al., 2018). Copyright 2018 Springer Nature.

(E) Demonstration of STDP learning rule in a Ag/ZnO/WS₂/Al synapse indicating the viability of 2D material-based synapses for unsupervised learning. Reprinted with permission from (Kumar et al., 2019). Copyright 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

(F) Low energy consumption of ∼400 fJ recorded in a 2D perovskite-based synapse, which is one order of magnitude higher than that of the biological synapse. Reprinted with permission from (Tian et al., 2017c). Copyright 2017 American Chemical Society.

(G) Near-linear weight update observed in a Ni/MoS₂/graphene synapse with an NLF of 0.276 along potentiation sustained for 15 cycles. Reprinted with permission from (Krishnaprasad et al., 2019). Copyright 2019 AIP Publishing.

(H) Biological synapse schematic with a modulatory input required for implementing heteroplasticity. Reprinted with permission from (He et al., 2020). Copyright 2020 American Chemical Society.

(I) Schematic illustration demonstrating a synapse utilizing a BP-based FET device. Reprinted with permission from (Tian et al., 2016). Copyright 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

(J) Implementation of both inhibitory and excitatory synapse with their corresponding inputs demonstrated using a back-gated MoS₂ FET by utilizing the gate terminal. Reprinted with permission from (Arnold et al., 2017). Copyright 2017 American Chemical Society.

(K) Weight update observed in ionic gate MoO₃ FET. Reprinted with permission from (Yang et al., 2017). Copyright 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

(L) Data retention of > 10⁴ s observed in graphene FET intercalated with Li⁺. Reprinted with permission from (Sharbati et al., 2018). Copyright 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.