Fabrication and performance study of 1T-VSe2@n-Si broadband self-driven Schottky-type photodetector

Due to the metallic nature of VSe2, which causes the high reverse current, studies on photodetector applications are very limited. In this study, a VSe2 film with a thickness of 71.49 nm was coated on n-type Si by the sputtering method to obtain a VSe2@n-Si junction device. Thus, we demonstrate a high-performance broadband Schottky-type photodetector (STPD) based on VSe2@n-Si with a high rectification ratio. XRD, field-emission scanning electron microscopy and energy-dispersive x-ray analysis of the VSe2 film were carried out. The low reverse current and high-performance broadband STPD based on VSe2@n-Si junction is studied in detail. I-V measurements in the presence of 365, 395, 590 and 850 nm irradiation of 8 mW cm−2 are also carried out. I-V measurements revealed that the VSe2@n-Si STPD has a high photoresponse in the UV-vis range. The VSe2@n-Si STPD demonstrated a broadband detection range with visible light and 590 nm responsivity of up to 10.78 (for 150 mW cm−2 vis), and ∼0.22 A W−1 (for 8 mW cm−2), respectively. Furthermore, the built-in electric field of the STPD enabled self-driven photodetection with an intrinsic specific detectivity of 4.14 × 1011 Jones and ON/OFF ratio of 1.1 × 105, respectively, at zero bias. Experimental results show that the fabricated VSe2@n-Si STPD is a suitable design for broadband and low-photon energy photodetectors.