Plasmonically engineered light-matter interactions in Au-nanoparticle/MoS₂ heterostructures for artificial optoelectronic synapse

Optoelectronic synaptic elements are emerging functional devices for the vigorous development of advanced neuromorphic computing technology in the post-Moore era. However, optoelectronic devices based on transition metal dichalcogenides (TMDs) are limited to their poor mobilities and weak light-matter interactions, which still hardly exhibit superior device performances in the application of artificial synapses. Here, we demonstrate the successful fabrication of Au nanoparticle-coupled MoS₂ heterostructures via chemical vapor deposition (CVD), where the light absorption of MoS₂ is greatly enhanced and engineered by plasmonic effects. Hot electrons are excited from Au nanoparticles, and then injected into MoS₂ semiconductors under the light illumination. The plasmonically-engineered photo-gating effect at the metal-semiconductor junction is demonstrated to create optoelectronic devices with excellent synaptic behaviors, especially in ultra-sensitive excitatory postsynaptic current (EPSC, 9.6 × 10^–3 nA@3.4 nW·cm^–2), ultralow energy consumption (34.7 pJ), long-state retention time (> 1,000 s), and tunable synaptic plasticity transitions. The material system of Au-nanoparticles coupled TMDs presents unique advantages for building artificial synapses, which may lead the future development of neuromorphic electronics in optical information sensing and learning.