Ultrabroadband Photodetector Based on Ferromagnetic van der Waals Heterodiode

The discovery of 2D ferromagnetic (FM) van der Waals (vdW) semiconductors with narrow bandgap and p-type transport behavior makes them promising for infrared photodetection. Here, a 2D vdW heterodiode uncooled long-wave infrared (LWIR) photodetector by stacking a p-type 2D FM material CrSiTe3 on top of an n-type transition metal dichalcogenides (TMDs) MoS2 is reported. A good rectification ratio >10(2) and an ultra-broadband photoresponse from 0.52 to 10.6 mu m are demonstrated. The photoresponsivity of up to 20.7 A W-1 and the external quantum efficiency (EQE) of up to 4031.7% are obtained under a 1310 nm laser at a -1 V bias in ambient, which indicates that these CrSiTe3-MoS2 p-n junction devices have a good photovoltaic response. Meanwhile, the photovoltaic responsivity up to 0.15 A W-1, EQE up to 29.7%, and fast response with a decay time of 2.8 mu s at 637 nm are demonstrated. In addition, the room temperature mid-wave infrared (MWIR) specific detectivity and LWIR specific detectivity of CrSiTe3-MoS2 is 6.1 x 10(9) cm Hz(1/2) W-1 and 1.93 x 10(9) cm Hz(1/2) W-1, respectively. These observations open up possibilities for developing high-sensitive infrared detection based on the valley optical selection rule and LWIR image technology.