High-Performance Broadband Visible?Near Infrared Photodetector Enabled by Atomic Capping Layer

摘要

This study employs an effective oxygen (O_2) plasma treatment to fabricatemultilayer molybdenum diselenide (MoSe_2) photodetectors for visible andnear-infrared (NIR) detection. With the introduction of O_2 plasma treatment,the atomic oxidized layer is generated to prevent direct interaction from O_2and water (H_20) molecules in air, leading to an improved environmentalstability. Meanwhile, bonded O atoms provide an electron-rich atmosphere,which can effectively reduce the intrinsic Se vacancies and generate a strongbuilt-in electric field to suppress the recombination of photocarriers. Asa result, the O_2-modified MoSe2 photodetector exhibits an excellent photoresponse,including a high responsivity of 889 mA W~(?1), a fast responsetime of 52 μs, and a high specific detectivity approaching 3.37 × 10~(14) Jonesunder 520 nm illumination with a light intensity of 2.02 mW cm~(?2) at 0.5 V.Moreover, the response spectra of MoSe_2-O_2 photodetectors can be furtherextended to NIR region (λ = 980 nm), owing to perturbation of O atoms inthe Se?Mo sublattice. Ultimately, a turbidity detection system based on theoptimized photodetector is demonstrated, which illustrates an accurate turbiditymeasurement with the concentration ranging from 0 to 4000 NTU.