Broadband artificial tetrachromatic synaptic devices composed of 2D/3D integrated WSe${}_2$-GaN-based dual-channel floating gate transistors

The development of artificial tetrachromatic vision holds great potential to enhance human color perception and discrimination, thereby enabling more effective navigation in diverse environments. Herein, an artificial tetrachromatic synaptic device is presented built upon 2D-3D vertically stacked semiconductors composed of tungsten diselenide (WSe${}_2$)-gallium nitride (GaN) configuration, forming a dual-channel floating gate transistor (FGT). Under the concerted influence of electrical and optical stimulation, the device successfully mimics fundamental tetrachromatic synaptic behaviors, including short-term potentiation (STP), weak long-term potentiation (wLTP), long-term potentiation (LTP), paired-pulse facilitation (PPF), spike number-dependent plasticity (SNDP), and spike rate-dependent plasticity (SRDP). Notably, the plasticity of the device can be further modulated under ultraviolet (UV) stimulation, providing insights into the modulation of synaptic plasticity through the photogenerated carrier dynamics in the GaN channel. These results imply that WSe${}_2$-GaN-based FGT architecture with dual-channel characteristics seamlessly integrates optical sensing and synaptic simulation functionalities, representing a promising avenue for the development of next-generation artificial visual perception systems (AVPS), with a particular advantage for the pursuit of high-performance artificial tetrachromatic neuromorphic computing applications of the future. (© 2024 Wiley‐VCH GmbH)