Multi-wavelength photodetector based on SnS2/Gr/SnS p-g-n trilayers with high responsivity and detectivity

A SnS 2 /graphene/SnS trilayer vdW heterojunction was constructed. • Graphene promotes charge transport and suppresses dark current. • The device achieves 5656.3 A W −1 responsivity at 405 nm. • Broadband detection from 405 to 850 nm is demonstrated. • Self-powered operation and imaging applications are achieved. Two-dimensional (2D) semiconductors are promising materials for broadband photodetection, benefiting from their favorable light–matter interaction and electrical properties. As an n-type layered semiconductor, SnS 2 is suitable for photodetection because carriers can move efficiently in it and incident light can be effectively absorbed, making it suitable for photodetection applications. In this work, SnS 2 /graphene/SnS (SnS 2 /Gr/SnS) trilayer van der Waals heterojunctions and corresponding photodetectors were fabricated and investigated. Owing to the graphene interlayer, which serves as both a carrier transport layer and a barrier layer, The detector responds to light over a wide spectral range, covering both the near-ultraviolet (NUV) and near-infrared (NIR) regions. Under 405-nm irradiation, the photodetector reaches an R value of 5656.3 A·W −1 and a D ⁎ value of 3.33 × 10 13 Jones. When the wavelength is extended to 850 nm, the responsivity remains 574.2 A·W −1 . The device also shows clear self-powered behavior, outperforming the conventional SnS 2 /SnS bilayer heterojunction photodetector. These results offer an effective strategy for improving SnS 2 -based broadband photodetectors and promotes their potential applications in optical communication and single-pixel imaging. Download: Download high-res image (225KB) Download: Download full-size image