Edge‐State–Driven Vertical MoS ₂ /Si Heterojunctions for Self‐Powered Broadband Photodetection and Physical‐Layer Intelligence

Vertically oriented low‐dimensional materials enhance optoelectronic devices through accessible edges and strong light‐matter interaction. However, a comprehensive understanding of their physical mechanisms and a validated device design for broadband self‐powered detection, ultralow‐noise output, and integrated optical processing are still lacking. This study explores the in‐situ synthesis of vertically aligned molybdenum disulfide (MoS 2 ) nanosheet arrays on silicon (Si) substrates, resulting in a vertical‐MoS 2 /Si heterojunction photodetector. This structure enhances the interfacial potential gradient, promotes edge‐state participation, and enables efficient separation and transport of photogenerated carriers. The photodetector demonstrates a stable, self‐powered photoresponse from 440–980 nm, maintains stability from 153–393 K, and operates continuously for over 4 months. It achieves a responsivity of 43 A/W and a specific detectivity of 2.6 × 10 12 Jones, and a low‐noise current power spectral density of 1.24 × 10 −20 A 2 /Hz, with rapid response times of 182 and 167 µs. The device detects light wavelengths and encodes spectral information with photoelectric responses. It uses optical logic gates and CNNs to accurately identify multi‐wavelength laser sources with over 95% accuracy. This research presents a framework to improve photodetectors, enhancing their ability to enable smarter perception and information processing.