Flexible Optical Synapses Based on In₂Se₃/MoS₂ Heterojunctions for Artificial Vision Systems in the Near-Infrared Range

Abstract

Near-infrared (NIR) synaptic devices integrate NIR optical sensitivity and synaptic plasticity, emulating the basic biomimetic function of the human visual system and showing great potential in NIR artificial vision systems. However, the lack of semiconductor materials with appropriate band gaps for NIR photodetection and effective strategies for fabricating devices with synaptic behaviors limit the further development of NIR synaptic devices. Here, a two-terminal NIR synaptic device consisting of the In2Se3/MoS2 heterojunction has been constructed, and it exhibits fundamental synaptic functions. The reduced band gap and potential barrier of In2Se3/MoS2 heterojunctions are essential for NIR synaptic plasticity. In addition, the NIR synaptic properties of In2Se3/MoS2 heterojunctions under strain have been studied systematically. The ΔEPSC of the In2Se3/MoS2 synaptic device can be improved from 38.4% under no strain to 49.0% under a 0.54% strain with a 1060 nm illumination for 1 s at 100 mV. Furthermore, the artificial NIR vision system consisting of a 10 × 10 In2Se3/MoS2 device array has been fabricated, exhibiting image sensing, learning, and storage functions under NIR illumination. This research provides new ideas for the design of flexible NIR synaptic devices based on 2D materials and presents many opportunities in artificial intelligence and NIR vision systems.

Weak Light‐Stimulated Synaptic Transistors Based on MoS2/Organic Semiconductor Heterojunction for Neuromorphic Computing

“…Figure 1b illustrates the Raman spectra of the monolayer MoS 2 with characteristic peaks of E 1 2g at 385.62 cm −1 and A 1g at 404.71 cm −1 , which were in accordance with the results reported in previous works. [ 35 , 36 ] The thickness of the monolayer MoS 2 confirmed by the atomic force microscopy (AFM) was only about 0.86 nm (Figure 1c), and the thickness of the MoS 2 /DNTT heterojunction film was about 55 nm (Figure S1, Supporting Information). Besides, the DNTT film was well crystallized and had a large grain size, which guaranteed the excellent performance of the MoS 2 /DNTT‐HPST.…”

Biomimetic Compound Eyes with Gradient Ommatidium Arrays

“…Recently, a study on Drosophila hyperacute 3D vision has been presented, which suggests a general dynamic stereoinformation sampling strategy that could potentially be combined with bionic gradient compound eyes to provide advanced machine vision in the future. Meanwhile, studies on optical synapses based on MoS 2 have been emerging with promising developments in image sensing, learning, and memory functions for artificial visual systems, − and these advanced technologies have the potential to be combined with gradient compound eyes to advance the research and applications of bionic compound eyes.…”

2D-Material-Based Volatile and Nonvolatile Memristive Devices for Neuromorphic Computing

“…In addition, the heterojunction can serve as a trapping center. − The generated carriers in the device move to the neighbor layers and lead to a change in the conductivity of the device. The existing barrier height can prevent the recombination of carriers in the device after removing the stimulations .…”