Artificial Optoelectronic Synapses Based on Ferroelectric Field-Effect Enabled 2D Transition Metal Dichalcogenide Memristive Transistors

Abstract

Neuromorphic visual sensory and memory systems, which can perceive, process, and memorize optical information, represent core technology for artificial intelligence and robotics with autonomous navigation. An optoelectronic synapse with an elegant integration of biometric optical sensing and synaptic learning functions can be a fundamental element for the hardware-implementation of such systems. Here, we report a class of ferroelectric field-effect memristive transistors made of a two-dimensional WS2 semiconductor atop a ferroelectric PbZr0.2Ti0.8O3 (PZT) thin film for optoelectronic synaptic devices. The WS2 channel exhibits voltage- and light-controllable memristive switching, dependent on the optically and electrically tunable ferroelectric domain patterns in the underlying PZT layer. These devices consequently show the emulation of optically driven synaptic functionalities including both short- and long-term plasticity as well as the implementation of brainlike learning rules. Integration of these rich synaptic functionalities into one single artificial optoelectronic device could allow the development of future neuromorphic electronics capable of optical information sensing and learning.

Optoelectronic synapse using monolayer MoS2 field effect transistors

“…Bulky circuitry converts the image captured for pattern recognition to electrical signals which are then interpreted by the neuromorphic hardware. An optoelectronic synapse, similar to the sensory neurons in the human eye, can detect light and store information through conductance states, enabling optical sensing, storage and processing of data in the same device 3 – 5 . Arguably, the idea of optoelectronic synapse originated from the demonstration of optically tuned resistance states in poly(3-octylthiophene-2,5-diyl) (P3OT)-coated carbon nanotube transistors using the charge detrapping at the P3OT/gate dielectric interface 6 .…”

Two-Dimensional Near-Atom-Thickness Materials for Emerging Neuromorphic Devices and Applications

“…When a voltage was applied to the PZT through the WS 2 , PZT forms the upward or downward ferroelectric domains underneath the WS 2 , leading to a positive or negative polarization to the surface areas, respectively. Therefore, it results in the accumulation or depletion of charges in the adjacent WS 2 channel ( Luo et al., 2020 ). Furthermore, Zhang et al.…”

“… (E) Demonstration of multilevel channel conductance by the application of a train of light pulses. Reprinted with permission from ( Luo et al., 2020 ). Copyright 2020 American Chemical Society.…”

Coalition of Thermo–Opto–Electric Effects in Ferroelectrics for Enhanced Cyclic Multienergy Conversion

“…Similar behavior could be obtained in multilevel memory storage devices based on ferroelectrics. [34] Still, in the measurement shown in Figure 3c, the material was again allowed to relax for one cycle before obtaining pyro-electro-optic modulation with À4 V, so as to have least contribution from the trapped current. Again, a significant leap in offset current and current density was observed, and three orders of increase in the magnitude of pyrocurrent suggest that the process can be used to have enhanced energy conversion or electrical output.…”