High-performance broadband, low-cost metal-semiconductor-metal π-SnS/Si photodetector

The UV-IR broadband photodetectors have attracted considerable attention for applications in telecommunications, environmental dust detection, and thermal imaging. Constructing broadband photodetectors based on multi-material heterostructures with multiple active absorber layers presents challenges related to complex interface engineering, increased costs, and reduced reproducibility, thereby limiting their practical applications. Metal-semiconductor-metal (M-S-M) photodetectors employ a single dominant photoactive absorption layer to achieve a broad photoresponse without requiring complex heterojunctions. Furthermore, the M-S-M design may achieve a gain greater than 1, resulting in an external quantum efficiency greater than 100%. This design also has other advantages, including planarity, simplified fabrication, and fast response times. Herein, we report a simple, cost-effective, and high-performance broadband (300-1000 nm) M-S-M photodetector based on a π-SnS film deposited on a silicon substrate via chemical bath deposition method. In this design, the π-SnS film serves as the primary photoactive material, while the underlying silicon substrate additionally contributes to photogeneration and carrier transport, particularly in the near-infrared region. The device exhibits a maximum responsivity of 2.42 × 10³ mA W^-1, a detectivity of 5.5 × 10¹¹ Jones, high sensitivity (3504), and a fast response time within the (36-90 ms) range. The present photodetector's features, including low-cost, rapid response, and a broad sensitivity range, make it suitable for broadband optoelectronic applications.