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Ferroelectric Domain Walls Enable Near-Infrared Visual Synapses in Wide-Bandgap 2D In-Plane Ferroelectric
Jun Fang1, Xianjun Zhang1, Pengfei Hou1
1Key Laboratory of Materials Design and Preparation Technology of Hunan Province, School of Materials Science and Engineering, Xiangtan University, Hunan Xiangtan 411105, China.
ACS Applied Materials & Interfaces
|June 26, 2026
Summary
Ferroelectric domain walls in a graphene heterojunction enable near-infrared (NIR) visual synaptic functions at ultralow voltages. This breakthrough advances 2D neuromorphic computing with polarization-sensitive, energy-efficient devices.
Area of Science:
- Materials Science
- Nanotechnology
- Neuromorphic Computing
Background:
- Ferroelectric domain walls enable sub-bandgap near-infrared (NIR) absorption in ferroelectric materials.
- Two-dimensional (2D) in-plane ferroelectric materials offer stable domain walls and optical polarization sensitivity for advanced devices.
- Developing efficient NIR visual synaptic functions is crucial for next-generation neuromorphic computing.
Purpose of the Study:
- To fabricate and investigate a graphene/NbOCl2/graphene heterojunction for NIR visual synaptic functions.
- To exploit the NIR light absorption properties of ferroelectric domain walls for ultralow voltage operation.
- To explore the device's polarization sensitivity and neuromorphic computing capabilities.
Main Methods:
- Fabrication of a multilayer graphene (Gr)/NbOCl2/Gr heterojunction using a 2D in-plane ferroelectric material.
- Characterization of the heterojunction's response to external bias, pulse frequency, and intensity across NIR wavelengths (808 nm-2200 nm).
- Evaluation of synaptic functions including paired-pulse facilitation/depression (PPF/PPD) and multipulse characteristics, alongside optical polarization sensitivity.
Main Results:
- The heterojunction successfully implemented synaptic functions at an ultralow voltage of 1 mV with minimal energy consumption (8.74 fJ per pulse).
- Nearly symmetric PPF/PPD characteristics were observed under positive and negative voltages, indicating robust synaptic behavior.
- Excellent optical polarization sensitivity was demonstrated, achieving a polarization ratio of 9.12 under 1064 nm illumination.
Conclusions:
- The developed heterojunction provides a viable platform for high-performance, 2D NIR polarization-sensitive visual synapses.
- This research offers significant technical and theoretical advancements for ferroelectric domain wall materials in neuromorphic computing.
- The findings accelerate the application of these materials in next-generation visual computing systems.
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