Ultrasensitive Solar‐Blind Ultraviolet Photodetector Based on FePSe3/MoS2 Heterostructure Response to 10.6 µm

Abstract Metal phosphorous tri‐chalcogenides are a category of new ternary 2D layered materials with a wide range of tuneable bandgaps (1.2–3.5 eV). These wide‐bandgap semiconductors exhibit great potential applications in solar‐blind ultraviolet (SBUV) photodetection. However, these 2D solar‐blind photodetectors suffer from low photoresponsivity, slow photoresponse speed, and narrow operation spectral region, thereby limiting their practical applications. Here, an ultra‐broadband photodetection based on a FePSe 3 /MoS 2 heterostructure with coverage ranging from solar‐blind ultraviolet 265 nm to longwave infrared (LWIR) 10.6 µm is reported. Notably, the device exhibits excellent weak light detection capability. A high photoresponsivity of 33 600 A W −1 and an external quantum efficiency of 1.57 × 10 7 % are demonstrated. A noise‐equivalent power as low as 5.7 × 10 –16 W Hz −1/2 and a specific detectivity up to 1.51 × 10 13 cm Hz 1/2 W −1 are realized in the SBUV region. The room temperature LWIR photoresponsivity of 0.12 A W −1 is realized. This work opens a route to design high‐performance SBUV photodetectors and wide spectral photoresponse applications.