Defect-Engineered Electrical Transport in SnS via Electron Beam Irradiation

Abstract

As a prototypical van der Waals layered monochalcogenide semiconductor, tin monosulfide (SnS) holds considerable promise for a wide range of applications owing to its distinctive physical properties. Conventional defect engineering strategies are predominantly confined to the material growth stage, which hinders localized, iterative post-fabrication modulation of electrical performance. Herein, we employ electron beam irradiation as a defect engineering strategy to systematically investigate the evolution of defect structures and electrical properties in multilayer SnS nanoflakes. Comprehensive spectroscopic and structural characterizations, along with density functional theory calculations, confirm that electron beam irradiation introduces abundant sulfur vacancies into the SnS lattice, with the vacancy concentration exhibiting a dose-dependent increase, as evidenced by Raman and X-ray photoelectron spectroscopy analyses. Electrical measurements demonstrate that the irradiated devices exhibit a current increase of two to five orders of magnitude and the pronounced suppression of gate dependence. This irradiation-induced electrical behavior is consistent with a hopping transport mechanism mediated by a percolation network of chalcogen vacancies. This study underscores the advantages of dose-controllable electron beam irradiation for defect engineering in layered SnS, providing critical guidance for rationally tailoring electrical properties in SnS and other layered chalcogenide semiconductors.