Dual-Mode Switching of Photodetection and Neuromorphic Photoelectric Memory in VS-ReS2/WSe2 Heterostructure via Vacancy and Electric Field Synergetic Regulation

Integrating photodetection and photoelectric memory functions into a single device, which enables high-efficiency signal processing and chip miniaturization, faces a great challenge due to the inherent speed discrepancy in their photoresponse characteristics. Herein, it is demonstrated the dual-mode switching of photodetection and neuromorphic photoelectric memory in a V_S-ReS₂/WSe₂ heterostructure. The sulfur vacancies (V_S) in ReS₂ induced by strong light irradiation together with the electric field can synergistically modulate the carrier transport in the heterostructure device. As result, under negative bias voltage, the device exhibits a photodetection function with ultrafast response speed (τ_rise = 6.63 µs, τ_decay = 6.28 µs) and strong polarization-dependence (anisotropy ratio: 4.0), which enables the device novel photoelectric logic outputs of “AND” and “OR” as well as high-resolution image sensing. Under positive bias voltage, the device exhibits a photoelectric memory function with fast optical writing and electrical erasing operations. The memory device can control and stabilize more than 128 operating states (7-bit), and it displays an over 10 years retention time. Furthermore, based on the dual-mode switching, the detection, memory, and recognition of handwritten digit images are completed in a single device. This work sheds light on the construction of novel multifunctional 2D optoelectronic devices for applications in artificial intelligence.