Correlation of Defect-Induced Photoluminescence and Raman Scattering in Monolayer WS2

Abstract

Defect investigation in two-dimensional transition-metal dichalcogenides (TMDs) is required because structural defects significantly affect the optical and electrical properties of TMD. Raman scattering can be an essential tool to study the defects in TMD, but defect-related Raman modes have been rarely studied. Here, we investigated the influence of sulfur vacancies and oxygen substitution on the optical properties of WS2using the laser irradiation technique. The defect-induced photoluminescence (PL) exhibits distinct features depending on the type of defects, which shows different changes in the intensities and peak positions of the excitons, biexcitons, and defect-bound excitons. Defect-activated Raman modes revealed information about the defects and demonstrated the origin of the alteration in PL. The defect analysis of TMDs based on the correlation between PL and Raman scattering provides a clear understanding of the variations in their optical properties.