High-performance broadband flexible photodetector based on Gd₃Fe₅O₁₂-assisted double van der Waals heterojunctions

Flexible photodetectors are fundamental components for developing wearable systems, which can be widely used for medical detection, environmental monitoring and flexible imaging. However, compared with 3D materials, low-dimensional materials have degraded performance, a key challenge for current flexible photodetectors. Here, a high-performance broadband photodetector has been proposed and fabricated. By combining the high mobility of graphene (Gr) with the strong light-matter interactions of single-walled carbon nanotubes (SWCNTs) and molybdenum disulfide (MoS₂), the flexible photodetector exhibits a greatly improved photoresponse covering the visible to near-infrared range. Additionally, a thin layer of gadolinium iron garnet (Gd₃Fe₅O₁₂, GdlG) film is introduced to improve the interface of the double van der Waals heterojunctions to reduce the dark current. The SWCNT/GdIG/Gr/GdIG/MoS₂ flexible photodetector exhibits a high photoresponsivity of 47.375 A/W and a high detectivity of 1.952 × 10¹² Jones at 450 nm, a high photoresponsivity of 109.311 A/W and a high detectivity of 4.504 × 10¹² Jones at 1080 nm, and good mechanical stability at room temperature. This work demonstrates the good capacity of GdIG-assisted double van der Waals heterojunctions on flexible substrates and provides a new solution for constructing high-performance flexible photodetectors.