Multifunctional Optoelectronic Synapse Based on Ferroelectric Van der Waals Heterostructure for Emulating the Entire Human Visual System

Abstract

The development of optoelectronic synapses can provide an important breakthrough toward creating a sophisticated and adaptable artificial visual system analogous to that of humans. However, it remains a great challenge to implement the various functions of the biological visual neuromorphic system at the single device level. Intriguingly, 2D van der Waals (vdW) heterostructure may offer a platform to address the issue. Here, a novel multifunctional synaptic device based on ferroelectric α-In 2 Se 3 /GaSe vdW heterojunction is proposed to emulate the entire biological visual system. Essential synaptic behaviors are observed in response to light and electrical stimuli; additionally, the retina-like selectivity for light wavelengths and the achievement of Pavlov's dog experiment demonstrate the device's capacity for processing complex electrical and optical inputs. Beyond the optoelectronic synaptic behaviors, the device incorporates memory and logic functions analogous to those in the brain's visual cortex. The results of artificial neural network simulations show that the vdW heterojunction-based device is completely capable of performing logic operations and recognizing images with a high degree of accuracy. The study indicates that versatile devices with a rationally designed construction have great potential for efficiently processing complex visual information and may simplify the design of artificial visual systems.

Emerging Optical In‐Memory Computing Sensor Synapses Based on Low‐Dimensional Nanomaterials for Neuromorphic Networks

“…So far, more and more attention has been attached to both electrical-control IMC and optical IMCS synapses based on low-dimensional materials with the effect of ferroelectric polarization, especially for ferroelectric materials based on 2D van der Waals system such as PbZr 0.2 Ti 0.8 O 3 (PZT), Bi 2 O 2 Se, and α-In 2 Se 3 . [114][115][116][117][118][119] However, no one has summarized the ferroelectric polarization mechanism of optical IMCS synapses with lowdimensional materials. In this section, systematic discussions on the ferroelectric polarization mechanism of 2D materials optical IMCS synapses will be investigated for the first time.…”

“…[119] The ideal Clausius-Mossotti (CM) model also pointed that the definition of polarization was the average dipole moment density. [118,119] Effective polarization (ΔP) was described as an integral function of the charge flow, as illustrated in the following equations…”

“…[119] As there was no inversion symmetry in the 2D plane, the spontaneous polarization occurred in the direction of in-plane, and the in-plane polarization direction was also associated with the out-plane polarization. [115,[117][118][119] Therefore, the coupling modulation of the electric field direction and the polarization direction could be obtained, which was helpful to the transition process from semiconductor characteristics to metal-like characteristics. [119] Zheng et al proposed an optical IMCS synapse based on 2D ferroelectric Bi 2 O 2 Se materials, as illustrated in Figure 12a.…”

Control of photocurrent and multi-state memory by polar order engineering in 2H-stacked α-In2Se3 ferroelectric

“…4d). This is different from 3R α-In 2 Se 3 that has the obvious photoresponse under the stimulation of light with appropriate wavelength [36]. It means that the photogenerated carriers cannot be separated quickly in the fresh 2H α-In 2 Se 3 .…”

High‐Performance Memristor Based on 2D Layered BiOI Nanosheet for Low‐Power Artificial Optoelectronic Synapses

“…The human retina with its simultaneous visual perception and information pre-processing capabilities in low power consumption provides great inspiration to designing artificial optoelectronic synaptic devices. [10] Recently, some optically modulated memristors and optoelectronic synapses have been explored based on 2D materials. [11] These optoelectronic synapses can be stimulated by both electrical and light inputs, which makes them promising for retina-like vision sensors.…”