Ultrafast Broadband Near‐Infrared Photodetector Based on High‐Quality SnS Thin Films

Tin sulfide (SnS), with its earth‐abundant, low‐cost, and nontoxic properties, shows promising potential as a next‐generation material for optoelectronic applications due to its tunable bandgap, high absorption coefficient, and excellent carrier mobility. However, challenges remain in fabricating high‐quality SnS thin films and achieving fast response times in diode‐type photodetectors. In this work, we optimized the deposition temperature and systematically investigated the material properties of SnS thin films. By introducing SnO 2 /TiO 2 and Spiro‐OMeTAD as electron and hole transport layers, respectively, we successfully fabricated SnS‐based photodiodes, which exhibited state‐of‐the‐art performance, including a high on‐off ratio exceeding 10 4 , low noise current close to 10 −12 A Hz −1/2 , high responsivity of 0.45 A W −1 and detectivity of ∼10 11 Jones at 810 nm, and fast response time of ∼1 µs. Furthermore, we demonstrated their application in flame detection, achieving faster response times compared to traditional devices. These results highlight the potential of SnS‐based photodetectors for practical applications in industrial safety systems.