Flexible artificial synapse with relearning function based on ion gel-graphene FET

Highlights: • The flexible artificial synapse based on ion gel-graphene FET can mimic excitatory and inhibitory functions of nerve synapse. • The artificial synapse circuit model in this paper can realize the integration of artificial synapse and circuits. • The ion gel-graphene artificial synapse can realize STP, LTP and PPF function of nerve synapse. • The ion gel-graphene artificial synapse has the function of memory, forgetting and relearning in the test. Due to its high-speed parallel processing, the human brain is superior to the von Neumann system computer in processing images, speech and perception. This paper proposes a flexible artificial synaptic device fabricated on graphene field effect transistors with ion gel. The channel with 100 µm is fabricated on a flexible substrate, and the weights of nerve synapses are adjusted by ion movement in the ion gel. The artificial synapse successfully mimics synaptic functions under low drain voltage (3 mV), such as excitatory postsynaptic current, inhibition postsynaptic current, paired-pulse facilitation and long-term plasticity with microampere current, and artificial synapse has a function similar to human forgetting and relearning. In order to integrate artificial synapse device with other circuits, the equivalent circuit of the artificial synapse simulates the plasticity of the synapse in this paper. These provide a new basis for the simulation and production of flexible artificial synapse, and the excellent long-term plasticity characteristics have huge application potential in memory functions.