Excellent synaptic behavior of lithium-based nano-ionic transistor based on optimal WO_2.7 stoichiometry with high ion...

Area of Science:

• Materials Science
• Neuroscience
• Electrical Engineering

Background:

• Artificial synapse devices are crucial for neuromorphic computing.
• Lithium-ion-based synaptic transistors offer promising characteristics but face challenges with transient conductance changes.

Purpose of the Study:

• To introduce a novel lithium (Li) ion-based three-terminal (3-T) synapse device.
• To investigate the role of tungsten oxide (WOx) stoichiometry on synaptic properties.
• To address transient conductance changes in ion-based synaptic transistors.

Main Methods:

• Fabrication of a 3-T synapse device with a WOx channel.
• Stoichiometry optimization to WO2.7.
• Analysis of Li-ion diffusivity using X-ray photoelectron spectroscopy and cyclic voltammetry.
• Implementation of a two-step voltage pulse scheme to manage conductance changes.

Main Results:

• Identified WO2.7 stoichiometry as optimal for synaptic characteristics, linked to Li-ion diffusivity.
• Demonstrated that oxygen deficiency in WOx creates an open-lattice structure, enhancing Li-ion injection and diffusion.
• Successfully resolved transient conductance changes, achieving symmetric and linear weight updates with reduced operation times.

Conclusions:

• The optimized WO2.7 stoichiometry and enhanced Li-ion diffusivity are key to high-performance artificial synapses.
• The proposed two-step voltage pulse scheme effectively mitigates transient conductance issues in ion-based synaptic transistors.
• This work advances the development of efficient and reliable neuromorphic computing hardware.