A Vis-SWIR Photonic Synapse with Low Power Consumption Based on WSe2/In2Se3 Ferroelectric Heterostructure

Neuromorphic visual sensory and memory systems that can sense, learn and memorize optical information have great potential in many areas such as image recognition and autonomous driving. However, most current artificial neuromorphic vision technology is suffering from large power consumptions (>100 pJ per switching), high circuitry complexity, and difficulty in miniaturization due to the physical separation of the optic sensing, processing, and memory units. Here, a photonic neuromorphic device based on WSe2/In2Se3 van der Waals (vdW) heterostructure is developed to meet the requirements of high-performance photonic synapse devices. Owing to the optically controlled ferroelectric polarization switching, the device shows light-tunable synaptic functions. For the first time, the light-stimulated synaptic behavior extends from visible light to short-wavelength infrared region (up to 1800 nm). Taking advantage of the ultra-low dark current of the heterojunction, the power consumption of the photonic synapse can be as low as 258 fJ per switching under a bias of -0.1 V, comparable to biological synapses. These findings demonstrate a novel photonic synapse, deepen the understanding of light-controlled polarization switching in semiconducting ferroelectric materials, and open up new application fields in multifunctional electronic and photonic devices based on 2D ferroelectric vdW heterostructures.