Porous Metal-Organic Framework/ReS2 Heterojunction Phototransistor for Polarization-Sensitive Visual Adaptation Emulation.

Visual adaptation allows organisms to accurately perceive the external world even in dramatically changing environments, from dim starlight to bright sunlight. In particular, polarization-sensitive visual adaptation can effectively process the polarized visual information that is ubiquitous in nature. However, such an intriguing characteristic still remains a great challenge in semiconductor devices. Herein, a novel porous metal-organic-framework phototransistor with anisotropic-ReS2 -based heterojunction is demonstrated for polarization-sensitive visual adaptation emulation. The device exhibits intriguing polarized sensitivity and an adaptive ability due to its strong anisotropic and trapping-detrapping characteristics, respectively. A series of polarization-sensitive neuromorphic behaviors like polarization-perceptual excitatory postsynaptic current, multimode adjustable dichroic ratio and reconfigurable sensory adaption, are experimentally demonstrated through this porous heterojunction phototransistor. More importantly, with the polarization-electricity cooperation strategy, advanced polarization-sensitive visual adaptation with strong bottom-gate control and environment dependence is successfully realized. These results represent a significant step toward the new generation of intelligent visual perception systems in autonomous navigation and human-machine interaction, etc.

Vertical 0.6 V sub-10 nm oxide-homojunction transistor gated by a silk fibroin/sodium alginate crosslinking hydrogel for pain-sensitization enhancement emulation.

The sensory nervous system of humans mainly depends on continuous training and memory to improve the pain-perceptional abilities for the complex noxious information in the real world and make appropriate responses. Unfortunately, the solid-state device for emulating this pain recognition with ultralow voltage operation still remains to be a great challenge. Herein, a vertical transistor with an ultrashort channel of ∼9.6 nm and ultralow voltage of ∼0.6 V based on protonic silk fibroin/sodium alginate crosslinking hydrogel electrolyte is successfully demonstrated. Such a hydrogel electrolyte with high ionic conductivity allows the transistor to work in an ultralow voltage, while the vertical transistor structure makes it have an ultrashort channel. Pain perception, memory, and sensitization can be integrated into this vertical transistor. Furthermore, using the photogating effect of light stimulus, the device displays multi-state pain-sensitization enhancement abilities through Pavlovian training. Most importantly, the cortical reorganization that reveals a close relationship among the pain stimulus, memory, and sensitization is finally realized. Therefore, this device can provide a great opportunity for multi-dimensional pain assessment, which is of great significance for the new generation of bio-inspired intelligent electronics, such as bionic robots, and smart medical equipment.

Polarization-perceptual anisotropic two-dimensional ReS2 neuro-transistor with reconfigurable neuromorphic vision.

Polarization is a common and unique phenomenon in nature, which reveals more camouflage features of objects. However, current polarization-perceptual devices based on conventional physical architectures face enormous challenges for high-performance computation due to the traditional von Neumann bottleneck. In this work, a novel polarization-perceptual neuro-transistor with reconfigurable anisotropic vision is proposed based on a two-dimensional ReS2 phototransistor. The device exhibits excellent photodetection ability and superior polarization sensitivity due to its direct band gap semiconductor property and strong anisotropic crystal structure, respectively. The fascinating polarization-sensitive neuromorphic behavior, such as polarization memory consolidation and reconfigurable visual imaging, are successfully realized. In particular, the regulated polarization responsivity and dichroic ratio are successfully emulated through our artificial compound eyes. More importantly, two intriguing polarization-perceptual applications for polarized navigation with reconfigurable adaptive learning abilities and three-dimensional visual polarization imaging are also experimentally demonstrated. The proposed device may provide a promising opportunity for future polarization perception systems in intelligent humanoid robots and autonomous vehicles.

2D electric-double-layer phototransistor for photoelectronic and spatiotemporal hybrid neuromorphic integration.

The hardware implementation of neuromorphic computing has attracted growing interest as a promising candidate for confronting the bottleneck of traditional von Neumann computers. However, most previous reports are focusd on emulating the synaptic behaviors by a mono-mode using an electric-driving or photo-driving approach, resulting in a big challenge to synchronously handle the natural photoelectric information. Herein, we report a multifunctional photoelectronic hybrid-integrated synaptic device based on the electric-double-layer (EDL) MoS2 phototransistor. Interestingly, the electric MoS2 synapse exhibits a potentiation filtering effect, while the photonic counterpart can implement both potentiation and depression filtering effects. Most importantly, for the first time, photoelectronic and spatio-temporal four-dimensional (4D) hybrid integration was successfully demonstrated by the synergic interplay between photonic and electric stimuli within a single MoS2 synapse. An energy band model is proposed to further understand such a photoelectronic and spatio-temporal 4D hybrid coupling mechanism. These results might provide an alternative solution for the size-scaling and intellectualization campaign of the post-Moore era, and for more sophisticated photoelectronic hybrid computing in the emerging neuromorphic nanoelectronics.

Transient security transistors self-supported on biodegradable natural-polymer membranes for brain-inspired neuromorphic applications.

Transient electronics, a new generation of electronics that can physically or functionally vanish on demand, are very promising for future "green" security biocompatible electronics. At the same time, hardware implementation of biological synapses is highly desirable for emerging brain-like neuromorphic computational systems that could look beyond the conventional von Neumann architecture. Here, a hardware-security physically-transient bidirectional artificial synapse network based on a dual in-plane-gate Al-Zn-O neuromorphic transistor was fabricated on free-standing laterally-coupled biopolymer electrolyte membranes (sodium alginate). The excitatory postsynaptic current, paired-pulse-facilitation, and temporal filtering characteristics from high-pass to low-pass transition were successfully mimicked. More importantly, bidirectional dynamic spatiotemporal learning rules and neuronal arithmetic were also experimentally demonstrated using two lateral in-plane gates as the presynaptic inputs. Most interestingly, excellent physically-transient behavior could be achieved with a superfast water-soluble speed of only ∼120 seconds. This work represents a significant step towards future hardware-security transient biocompatible intelligent electronic systems.

Coplanar Multigate MoS2 Electric-Double-Layer Transistors for Neuromorphic Visual Recognition.

Spatial coordinate and visual orientation recognition in cortical cells play important roles in the visual system. Herein, spatiotemporally processed visual neurons are mimicked by a facile coplanar multigate two-dimensional (2D) MoS2 electric-double-layer transistor with proton-conducting poly(vinyl alcohol) electrolytes as laterally coupled gate dielectrics. Fundamental neuromorphic behaviors, e.g., excitatory postsynaptic current and paired-pulse facilitation, were successfully mimicked. For the first time, a proof-of-principle artificial visual neural network system for mimicking spatiotemporal coordinate and orientation recognition was experimentally demonstrated in such devices. The experimental results provide a promising opportunity for adding intelligent spatiotemporally-processed functions in emerging brain-like neuromorphic nanoelectronics.