A neuromorphic device mimicking synaptic plasticity under different body fluid K^(+) homeostasis for artificial reflex path construction and pattern recognition

The ionic environment of body fluids influences nervous functions for maintaining homeostasis in organisms and ensures normal perceptual abilities and reflex activities.Neural reflex activities,such as limb movements,are closely associated with potassium ions(K+).In this study,we developed artificial synaptic devices based on ion concentration-adjustable gels for emulating various synaptic plasticities under different K+concentrations in body fluids.In addition to performing essential synaptic functions,potential applications in information processing and associative learning using short-and long-term plasticity realized using ion concentration-adjustable gels are presented.Artificial synaptic devices can be used for constructing an artificial neural pathway that controls artificial muscle reflex activities and can be used for image pattern recognition.All tests show a strong relationship with ion homeostasis.These devices could be applied to neuromorphic robots and human-machine interfaces.

Ferro-floating memory:Dual-mode ferroelectric floating memory and its application to in-memory computing

Various core memory devices have been proposed for utilization in future inmemory computing technology featuring high energy efficiency.Flash memory is considered as a viable choice owing to its high integration density,stability,and reliability,which has been verified by commercialized products.However,its high operating voltage and slow operation speed issues caused by the tunneling mechanism make its adoption in in-memory computing applications difficult.In this paper,we introduce a dual-mode memory device named“ferro-floating memory”,fabricated using van der Waals(vdW)materials(h-BN,MoS2,andα-In2Se3).The vdW material,α-In2Se3,acts as a polarization control layer for the ferroelectric memory operation and charge storage layer for the conventional flash memory operation.Compared to the tunnelingbased memory operation,the ferro-floating memory operates 1.9 and 3.3 times faster at 6.7 and 5.8 times lower operating voltages for programming and erasing operations,respectively.The dual-mode operation improves the linearity of conductance change by 5 times and the dynamic range by 48%through achieving conductance variation regions.Furthermore,we assess the effects of the variation in device operating voltage on neural networks and suggest a memory array operating scheme for maximizing the networks'performance through various training/inference simulations.