Design and implementation of an infrared artificial visual neural synapse based on a p-WSe2/n-Ta2NiS5 van der Waals heterojunction

Two-dimensional heterojunctions, capable of capturing, processing, and memorizing optical signals, have vast potential for diverse applications in simulating visual neural synapses. However, a significant gap exists in the availability of two-dimensional heterojunctions capable of responding to infrared light, particularly enabling the realization of detection, sensing, and memory behavior under infrared light stimuli with wavelengths exceeding 1000 nm. In this report, a multipurpose infrared artificial visual neural synapse based on a p-WSe₂/n-Ta₂NiS₅ van der Waals heterojunction is designed. The heterojunction demonstrates self-powered infrared photodetection performance driven by the built-in electric field. Simultaneously, the tuning of energy band type through bias-induced band bending enables it to function as a photoelectric synapse. The heterojunction successfully simulates synaptic behaviors, with the perception wavelength extending into the infrared region (1064 and 1550 nm). Moreover, according to the synaptic plasticity of this heterojunction, a 3 × 3 visual image array is assumed to show image perception, image memory ability, and application prospects in information filtering and dynamic capture. This work not only offers an avenue to integrate multiple functions into a single heterojunction, but also provides the opportunity to implement advanced infrared artificial vision systems.