High‐Performance Broadband Visible−Near Infrared Photodetector Enabled by Atomic Capping Layer

Abstract

AbstractThis study employs an effective oxygen (O2) plasma treatment to fabricate multilayer molybdenum diselenide (MoSe2) photodetectors for visible and near‐infrared (NIR) detection. With the introduction of O2 plasma treatment, the atomic oxidized layer is generated to prevent direct interaction from O2 and water (H20) molecules in air, leading to an improved environmental stability. Meanwhile, bonded O atoms provide an electron‐rich atmosphere, which can effectively reduce the intrinsic Se vacancies and generate a strong built‐in electric field to suppress the recombination of photocarriers. As a result, the O2‐modified MoSe2 photodetector exhibits an excellent photoresponse, including a high responsivity of 889 mA W−1, a fast response time of 52 µs, and a high specific detectivity approaching 3.37 × 1014 Jones under 520 nm illumination with a light intensity of 2.02 mW cm−2 at 0.5 V. Moreover, the response spectra of MoSe2‐O2 photodetectors can be further extended to NIR region (λ = 980 nm), owing to perturbation of O atoms in the Se−Mo sublattice. Ultimately, a turbidity detection system based on the optimized photodetector is demonstrated, which illustrates an accurate turbidity measurement with the concentration ranging from 0 to 4000 NTU.