Nanoresonance Cavity and Localized Surface Plasmon Resonance Enhanced Broad-Spectral Photodetector for Versatile Applications.

To overcome the limitations inherent in traditional silicon (Si)-based photodetectors, particularly the low light absorption and complex carrier dynamics, this study proposes and fabricates in situ three-dimensional (3D) graphene/Si Schottky junctions integrated with WS quantum dots (QDs). The introduction of WS QDs enables the heterojunction to realize "double-enhanced absorption" by the synergistic effect of the natural nanoresonant cavity effect and the surface plasmon resonance effect (LSPR) of the WS QDs. Photodetectors constructed from the WS QDs/3D-graphene/Si heterojunction demonstrate a broadband, self-powered response from 440 to 1850 nm, maintaining stable operation at 1550 nm for 4 months. They exhibit high-frequency modulation (2 kHz), a responsivity of up to 83 A/W, a specific detectivity of 5.6 × 10 Jones, rapid response/recovery times of 139 μs/145 μs with multifunctionality in image acquisition, information encryption, and logic operations. This research lays the foundation for high-performance, stable photodetectors and light-controlled logic circuits in communications and imaging.