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Black phosphorus (BP) as a promising candidate for mid-wave infrared (MWIR) detection has attracted much attention. However, the high-speed photoresponse at the MWIR is yet to be a challenge. In this paper, we report a BP-graphene heterostructure photodetector with fast photoresponse at MWIR range using molybdenum electrode as a contact to realizing a low Schottky barrier. The device exhibits a fast photoresponse in a broad-spectrum range from visible to MWIR (0.67–4.2 μ m). A high photovoltaic responsivity up to 183 mA W ^−1 and EQE up to 35.6% were realized at the visible range of 0.637 μ m light and respectively 7.9 mA W ^−1 and 0.31% at MWIR 3098 nm. The specific detectivity D * = 6.69 × 10 ^8 Jones is obtained at 1 mV bias under the illumination of the MWIR 4.25 μ m in the ambient condition. Our work may open a new way to realizing fast MWIR photoresponse at the low light level.

Epitaxial graphene (EG) on semi-insulating SiC prepared by a thermal decomposition method is the most promising strategy for graphene application in large-scale integrated circuits due to compatibility with current semiconductor processes. In this study, high-quality few-layer graphene (FLG) was epitaxially grown on the semi-insulating on-axis 4H-SiC by microwave plasma chemical vapor deposition (MPCVD). Both sides of the SiC substrate were etched with H _2 plasma at ∼1000 °C to promote the nucleation and the growth of graphite before epitaxial growth. The surface morphology and properties of EG on SiC (0001) were measured by energy-dispersive x-ray (EDX), x-ray photoelectron spectrogram (XPS), and atomic force microscope (AFM). The qualities of EG grown on the two surfaces of SiC at various temperatures were checked by Raman spectroscopy. Furthermore, the EG growth was controlled by the effect of Ar plasma in the MPCVD and the few-layer (1–3 layers) high-quality EG films were formed on SiC (000 $\overline{1}$ ). The room temperature Hall mobility of EGs up to 2790 cm ^2 V ^−1 s ^−1 on SiC(000 $\overline{1}$ ) was realized.