Wafer-scale synthesis of 2D dirac heterostructures for self-driven, fast, broadband photodetectors

Type-II Dirac semimetal platinum ditelluride (PtTe2) is a promising functional material for photodetectors because of its specially tilted Dirac cones, strong light absorption, and high carrier mobilities. The stack of two-dimensional (2D) Dirac heterostructures consisting of PtTe2 and graphene could overcome the limit of detection range and response time occurring in the heterostructures of graphene and other low-mobility and large-gap transition metal dichalcogenides (TMDs). Here, we report an approach for achieving highly controllable, wafer-scale production of 2D Dirac heterostructures of PtTe2/graphene with tunable thickness, variable size, and CMOS compatibility. More importantly, the optimized recipes achieve the exact stoichiometric ratio of 1:2 for Pt and Te elements without contaminating the underlayer graphene film. Because of the built-in electric field at the junction area, the photodetectors based on the PtTe2/graphene heterostructure are self-driven with a broadband photodetection from 405 to 1850 nm. In particular, the photodetectors have a high responsivity of up to 0.52 AW-1 (without bias) and a fast response time of 8.4 μs. Our work demonstrated an approach to synthesizing hybrid 2D Dirac heterostructures, which can be applied in the integration of on-chip, CMOS-compatible photodetectors with near-infrared detection, high sensitivity, and low energy consumption.