Response Speed-Tunable Photodetectors Based on Hybrid Ternary FePSe_3 Nanoflakes

摘要

The layered metal phosphorus trichalcogenides (MPTs) are a newly emergingvan der Waals material family with bandgaps ranging from 1.3 to 3.5 eV, whichare promising candidates for optoelectronic devices. By using the excitedmultiple energy levels of FePSe_3, a high-performance FePSe_3 photodetector,which shows tunable response speed in the range of ultraviolet (UV) tonear-infrared (NIR), is designed. The FePSe_3 photodetector exhibits a highphotoresponsivity of 236.18 A·W~(?1) under 532 nm laser illumination (laserpower density P = 1 mW cm~(?2)). The properties of FePSe_3 can be modulatedby oxygen plasma treatment, which transfer to oxygen-doped FePSe_3(FePSe_3-O). Moreover, the speed of the FePSe_3-O photodetector can beimproved more than 240 times compared to the intrinsic FePSe_3photodetector under NIR illumination (λ = 808 nm). In addition, theFePSe_3-graphene heterojunction can significantly improve thephotoresponsivity and simultaneously prolong the response time of thedevice due to the FePSe_3/graphene interfacial barrier. These results suggestthat intrinsic, doped FePSe_3 and its heterojunction can be used asmultifunctional photodetectors with tunable response speeds.