The Research Of Flexible Artificial Synapse Based On Ion Gel Field Effect Transistor

More intelligent computers are required in the machine learning,emotion perception,intelligent robots with the rapid development of artificial intelligence,but the classic von Neumann computer system can no meet the current computing needs.In contrast,neuromorphic computing has functions such as image and speech recognition,control,reasoning,learning,and perception,and its high-speed parallel computing method has the characteristics of low power consumption and high efficiency.This thesis is inspired by the structure of biological synapse,a flexible artificial synapse based on graphene and ion gel field effect transistor is designed,which provide feasible solutions for neuromorphic computing.The main research content of the thesis is arranged as follows:The artificial synapse proposed in this thesis is based on the structure of the field effect transistor,and the screen-printing technology is used to print source and drain electrodes on the surface of flexible graphene.The solid electrolyte ion gel as the gate medium simulates the movement of neurotransmitters.The electric double layer(EDL)formed on the surface of graphene realizes the modulation of graphene.Its innovation is the production of a fully flexible artificial synapse device by ion gel and graphene.Firstly,this thesis establishes an equivalent circuit to simulate the movement of ions in the EDL,and establishes an equivalent circuit model of the artificial synapse device based on the field effect transistor large signal model.Through calculation and formula derivation,the characteristics of source-drain current under different gate voltage are analyzed.The functions of excitatory postsynaptic current(EPSC),inhibitory postsynaptic current(IPSC),paired-pulse facilitation(PPF),short-term plasticity(STP),and long-term plasticity(LTP)of synapses are realized through simulation.Secondly,the influence of the gate voltage amplitude,polarity and duration on the output current was tested with Agilent B1500 A.The synaptic EPSC,IPSC,PPF,STP and LTP functions were successfully mimicked.Finally,the application of artificial synapse devices is discussed in this thesis,and a corresponding memory array based on the LTP of artificial synapse devices is designed.Experiments prove that the flexible graphene ion gel artificial synapse device proposed in this thesis can successfully simulate synapse functions,and provides a new solution for the application of bionic neuromorphic computing in the field of artificial intelligence and flexible circuits.