Gate‐Tunable Photodiodes Based on Mixed‐Dimensional Te/MoTe2 Van der Waals Heterojunctions

Abstract The dangling‐bond‐free surfaces of 2D materials enable them to possess various degrees of freedom to form heterostructures with non‐2D materials. This allows for the combination of the advantages of different dimensional materials to fabricate van der Waals (vdW) heterostructures, thereby improving device performance and even bringing diversity and novelty. Herein, a mixed‐dimensional vdW heterostructure photodiode comprising a 1D tellurium (Te) nanowire and a 2D molybdenum ditelluride (MoTe 2 ) flake is demonstrated. Forward rectifying and backward rectifying characteristics are realized by applying different gate voltage. The device displays a broad spectral response from visible to near‐infrared and exhibits ultrahigh external quantum efficiency of 7.16 × 10 3 % for photogating effect. Moreover, the response time can be improved by controlling gate voltage and a rapid response time of 4.8 ms is achieved. These mixed‐dimensional vdW heterojunctions, which take advantages of both 1D and 2D semiconductors, will facilitate the development of next‐generation electronics and optoelectronics.