Multimode Operation of Light-Gated Transistors Based on Millimeter-Scale Transition-Metal Dichalcogenide Grown by Chemical Vapor Deposition

The operation of conventional transistors involves electrostatically gated control over the deposited dielectric layers; however, the integration of electric gating into optoelectrical transistors can result in thermal noise or fabrication complexity. Herein, chemical-vapor-deposition-grown millimeter-scale WSe 2 flakes were used to construct light-gated transistors (LGTs) suitable for single-device logic operations. Different LGT behaviors were observed at above- and below-threshold light-gating powers upon different pulse modulations: the LGTs exhibited high sensitivity and cycling stability within a broad range of operating frequencies at a below-threshold light power. Light-gated logic above-threshold power enabled single-device logic operations under simultaneous electric and light gating, whereas a transition to light-triggered synaptic operation occurred for laser pulse modulation under above-threshold light. In the synaptic mode, the LGTs mimicked bioinspired synaptic functionalities suitable for neuromorphic computing, thus holding promise for the fabrication of optically operated in-sensor computing hardware that exhibits multifunctionality suitable for the realization of multimodal interfaces and artificial intelligence.