High-performance broadband WO3−x/Bi2O2Se photodetectors based on plasmon-induced hot-electron injection.

Two-dimensional (2D) Bi₂O₂Se has emerged as a promising candidate for broadband photodetection, owing to its superior carrier mobility, outstanding air-stability, and suitable bandgap. However, Bi₂O₂Se photodetectors suffer limited sensitivity at a near-infrared region due to the relatively weak light absorption at this band. Here, it is demonstrated that coupling with plasmonic nanostructures can effectively improve the performance of Bi₂O₂Se photodetectors at a broad spectral range of 532–1550 nm. By virtue of plasmon-induced hot-electron injection and the improved light absorption, the WO_3−x/Bi₂O₂Se hybrid photodetector exhibits a high responsivity of ∼1.7 × 10⁶ A/W at 700 nm, and ∼48 A/W at a communication O-band of 1310 nm, which is nearly one order of magnitude higher than that of an intrinsic Bi₂O₂Se device. Moreover, profited by ultrafast hot electron transfer and the avoided defect trapping, the device maintains a high-speed photoresponse (rise time ∼326 ns, decay time ∼47 μs). Our results show that 2D materials coupled with plasmonic nanostructures is a promising architecture for developing state-of-the-art broadband photodetection. [ABSTRACT FROM AUTHOR]