Photodetection Enhancement of PdSe2/ReSe2 Van der Waals Heterostructure Field-Effect Transistors: A Density Functional Theory-Guided Approach

The fabrication of van der Waals heterostructures (vdWHs) has drawn considerable interest because of their wide range of functionalities. Herein, a novel PdSe2/ReSe2 vdWHs with gate-tunable rectification behavior and excellent broadband photodetection characteristics is presented. The application of the gate bias substantially enhances the rectification behavior, with the highest rectification ratio (approximate to 3.13 x 10(3)) observed at gate voltage V-g = -60 V. The density functional theory calculations demonstrate the direct and indirect bandgap behavior of PdSe2 and ReSe2 in the monolayer structure, respectively. Additionally, the PdSe2/ReSe2 heterojunction displays a strong photo-response in the near-infrared region and achieves a high photoresponsivity, an excellent external quantum efficiency, and rapid rise and decay times of 1.7 x 10(3) A W-1, 4.05 x 10(3), and 5 and 20 ms, respectively. Furthermore, the device exhibits a remarkable detectivity of approximate to 3.5 x 10(12) Jones. The findings hold great potential for advancing the fabrication of multifunctional vdW heterostructure devices.