Mixed-dimensional Integration for Tetrachromatic Optoelectronic Synaptic Devices Based on 2D/3D WSe₂-GaN

Mixed-dimensional heterostructures (MDHs) open up new opportunity for next-generation optoelectronic synaptic devices by simulating the integrated functions of the human visual system. In this work, we proposed a dual-channel WSe<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>/GaN 2D/3D integrated optoelectronic synaptic device exhibiting synaptic characteristics to broadband wavelengths in ultraviolet-visible range and demonstrating a comprehensive set of emulating basic optoelectronic synaptic characteristics. Notably, the device’s plasticity is tunable at different wavelengths, which is attributed to the different photogenerated carrier dynamics in the WSe<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>-GaN channel under ultraviolet and visible light stimulation. This work proposes a significant milestone of MDH-based artificial synapses solely utilizing their individual optoelectronic features, which is attractive toward scaled-up neuromorphic architectures.