Two-dimensional semiconductor transistors simulate synaptic behavior stimulated by drugs｜npj 2D Materials and Applications

Nerve stimulation of drugs can cause short-term or continuous changes in synaptic excitability.
This change in synaptic plasticity is not only the mechanism of brain learning and memory, but also an important basis for reflecting the effects of drugs
.

Two-dimensional layered semiconductor materials have the advantages of atomic layer thickness, large volume ratio and excellent charge transfer ability, and are expected to be widely used in the fields of transistors, photodetectors, sensors, memories, and neuromorphic hardware
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Recently, the team of Academician Chu Junhao/Professor Li Wenwu of East China Normal University found that the two-dimensional semiconductor field effect transistor based on the back gate structure can adjust the channel current between the source and drain of the field effect transistor through the gate, which can be used in electronic devices.
Achieve the simulation of synaptic plasticity horizontally
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The team used the excellent gate control ability and photosensitivity of the two-dimensional semiconductor material-indium selenide (InSe) to fabricate charge trap assisted transistor-type synaptic devices, and successfully simulated the synaptic plasticity after the action of drugs
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The research results were published in npj 2D Materials and Applications 5, 60 (2021) with the title "Carrier-capture-assisted Optoelectronics Based on van der Waals Materials to Imitate Medicine-acting Metaplasticity"
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Under the action of gate electric field and light pulse, schematic diagram of synapse simulation mechanism of InSe transistor The transistor adopts a back-gate structure, InSe is used as the channel layer, and a discontinuous In layer is deposited on the surface to achieve surface charge doping and encapsulation protection The effect
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The team cleverly used the inherent trap state at the InSe/SiO2 interface to control the polarity of the gate electric field to induce continuous capture/release of charge at the interface
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Under the combined action of different gate electric fields and light pulses, the InSe channel exhibits a completely different photoconductivity relaxation phenomenon, similar to the modulation of synaptic plasticity
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This phenomenon is used to successfully simulate the three-state behavior of nerve synapse weight enhancement, stability and weakening, which is different from the single weight change trend of other tasks, and can truly reflect the efficacy of patients under different drug doses (effective/stable/ineffective)
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In addition, by adjusting the light stimulation parameters (including the frequency and number of light pulses) to simulate the frequency and number of medications, the plasticity of the nerve synapses under the action of real drugs is further restored
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The study proved the feasibility and significance of using a single InSe transistor to simulate the efficacy of drugs, and opened up new ideas for the development of next-generation neuromorphology, artificial intelligence and biomedical engineering
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This research work was completed with East China Normal University as the first unit, master student Nie Qianfan and PhD student Gao Caifang as co-first authors, and Professor Li Wenwu from the team of Academician Chu Junhao from East China Normal University as the corresponding author (Email: wwli@ee.
ecnu.
edu .
cn)
.

The research work was also supported by Professor Lin Yanfu and Dr.
Li Mengjiao from Chung Hsing University in Taiwan, as well as the National Natural Science Foundation of China and the Shanghai Natural Science Foundation of China
.

© naturedoi: 10.
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