Memristive Synapse with High Reproducibility for Flexible Neuromorphic Networks Based on Biological Nanocomposites
Memristive synapses from biomaterials are promising for building flexible and implantable artificial neuromorphic systems due to their remarkable mechanical and biological properties. However, these biological devices are limited to relatively poor memristive switching characteristics, and thus fail to meet the requirement of neuromorphic networks for high learning accuracy. Here, memristive synapses based on carrageenan nanocomposites that possess desired characteristics are demonstrated. The device shows high reproducible analog resistive switching behaviors with 250 conductance states, low write noise, good write linearity, high retention of more than 10^4 s and endurance for at least 10^6 pulses. The enhanced switching properties are attributed to controllable and confined conductive filament growth, owing to the synergistic effect of self-assembled silver nanoclusters doping and nanocone-shape electrode contact. Moreover, the device exhibits excellent reliability under 1000 bending tests. Simulations including the non-ideal factors prove that the synaptic device array can operate with an online learning accuracy of 94.3%. These findings enable broader applications of biomaterials in flexible memristive devices and neuromorphic systems.