Giant‐Enhanced SnS2 Photodetectors with Broadband Response through Oxygen Plasma Treatment

Abstract Layered tin disulfide (SnS 2 ) is a vital semiconductor with versatile functionality due to its high carrier mobility and excellent photoresponsivity. However, the intrinsic defects V s (sulfur vacancies), which cause Fermi level pinning (significant metal contact resistance), hinder its electrical and optoelectrical performance. Herein, oxygen plasma treatment is employed to enhance the optoelectronic performance of SnS 2 flakes, which results in artificial sub‐bandgap in SnS 2 . Consequently, the broadband photosensing (300–750 nm) is remarkably improved. Specifically, under 350 nm illumination, the O 2 ‐plasma‐treated SnS 2 photodetector exhibits an enhanced photoresponsivity from 385 to 860 A W −1 , the external quantum efficiency and the detectivity improve by one order of magnitude as well as increase the photoswitching response improvement by two orders of magnitude for both rising (τ r ) and decay (τ d ) time. This artificial sub‐bandgap can both improve the photoresponse and broaden the response spectra, which paves a new path for the applications of optoelectronics.