WSe₂/graphene heterojunction synaptic phototransistor with both electrically and optically tunable plasticity

Abstract

The imitation of synaptic plasticity in artificial neuromorphic devices has been widely realized based on memristors, transistors and ion devices. This development of artificial synaptic devices is expected to open up a new era for neuromorphic computing. However, the complicated functions in biological synapse are dependent on the dynamic neural activities with modulated plasticity, which is still very difficult to emulate at the device level. Here, an artificial synaptic transistor based on WSe2/graphene van der Waals heterojunction is demonstrated with both electrically and optically modulated synaptic plasticity. By changing the polarity of applied V gs and V ds as well as superimposed gate voltage spikes, both excitatory and inhibitory synaptic plasticity can be realized in a single device. Moreover, due to the asymmetric optical response of WSe2/graphene heterojunction, optical modulation on hysteretic behaviors is achieved and also contributes to the inversion of synaptic plasticity. Hence, this work demonstrates a coordinated regulation on synaptic plasticity under electrical and optical stimuli and provides a multi-dimensional modulation strategy to understand the underlying mechanisms of complicated neuromorphic computing and further develop multifunctional neuromorphic optoelectronics.

Applications of Graphene in Five Senses, Nervous System, and Artificial Muscles

“…By each sensory organ, the receptive field is transduced into the changes in electric current or potential, which can be transmitted by signaling pathways and fused with other senses in the brain. The graphene memristor based individual artificial synapse , can transmit a pulse signal, and graphene synapse arrays host the neuromorphic computing for memory and data processing . Upon stimulus to skin or electronic skin, , the human responds by nervous reflexes or the brain system.…”

Equalizing Excitation‐Inhibition via the Ambipolar Photoresponse of Al2O3/graphene Hybrid Neuromorphic Devices

“…[5][6][7][8] Thus, reproducing biological synaptic plasticity is highly desired for realizing brain-inspired neuromorphic and hardware-based artificial intelligence. [9][10][11][12] Over the past ten years, some essential synaptic functions, such as neurotransmitter release, excitatory postsynaptic current (EPSC), long-term depression (LTD) or potentiation (LTP) of postsynaptic currents, spike-timing-dependent plasticity (STDP), have been successfully reproduced in various nanoscale electronic devices, including memristors, [13][14][15] fieldeffect transistors, [16][17][18] and ferroelectric tunnel junctions. [19][20][21] In particular, photoelectronic synapses have been rapidly developed, such as phototransistors and photomemristors, which enable flexible implementation of synaptic plasticity due to more modulation channels.…”

Programmable van‐der‐Waals heterostructure‐enabled optoelectronic synaptic floating‐gate transistors with ultra‐low energy consumption

“…Several strategies have been proposed to achieve plasticity modulation, including the transition from short‐term plasticity (STP) to long‐term plasticity (LTP) by chemical composition engineering, 18 the conversion between inhibition and excitation by gate voltage tuning, 20 and an improvement on plasticity symmetry by chemical doping 21 . However, the synergistic modulation in both electrical and optical ways, which may contribute to an emulation on complex synaptic activities in neural vision systems, is still not well explored in optoelectronic synaptic devices based on vdW heterostructures 22 . Therefore, to fully achieve neuromorphic information processing at the device level, designed device structure, and novel operation principles are required to enable the emulation and modulation of optoelectronic synaptic plasticity.…”

“…21 However, the synergistic modulation in both electrical and optical ways, which may contribute to an emulation on complex synaptic activities in neural vision systems, is still not well explored in optoelectronic synaptic devices based on vdW heterostructures. 22 Therefore, to fully achieve neuromorphic information processing at the device level, designed device structure, and novel operation principles are required to enable the emulation and modulation of optoelectronic synaptic plasticity.…”