Realizing Electronic Synapses by Defect Engineering in Polycrystalline Two-Dimensional MoS₂ for Neuromorphic...

Area of Science:

• Materials Science
• Nanotechnology
• Computer Engineering

Background:

• Two-dimensional transition-metal dichalcogenides (2D TMDs) offer unique properties for advanced electronic devices.
• Neuromorphic computing aims to mimic the human brain's structure and function.
• Artificial synaptic devices are crucial components for neuromorphic systems.

Purpose of the Study:

• To fabricate and characterize artificial synaptic devices using sulfur-defect-assisted molybdenum disulfide (MoS₂).
• To investigate the impact of sulfur vacancy engineering on synaptic behavior and memory characteristics.
• To analyze the working mechanism of these devices for potential neuromorphic applications.

Main Methods:

• Fabrication of MoS₂ films using a sputtering process.
• Precise sulfur (S) vacancy-engineering for defect control.
• Comprehensive electrical, physical, and microscopy characterizations to analyze device performance and mechanism.

Main Results:

• Sputtered MoS₂ films without vacancy control showed no synaptic behavior.
• Sulfur vacancy-controlled MoS₂ films exhibited excellent synaptic functions.
• Devices demonstrated remarkable nonvolatile memory characteristics: high switching ratio (~10³), large memory window, and long retention time (~10⁴ s).
• Synaptic functions like paired-pulse facilitation (PPF) and long-term potentiation/depression (LTP/LTD) were observed.

Conclusions:

• Sulfur vacancy engineering is a viable strategy for creating high-performance artificial synaptic devices from MoS₂.
• The developed MoS₂ synaptic devices are CMOS-compatible, scalable, low-cost, and facile to fabricate.
• This work provides a guideline for designing practical 2D TMD-based neuromorphic computing systems.