Defect hydrogenation in monolayer transition metal dichalcogenides

Structural defects in two-dimensional semiconducting transition metal dichalcogenides (TMDs) play an important role in modifying their physical properties. In this talk, we will present our optical spectroscopic study on the defect engineering of monolayer TMDs through hydrogenation. Photoluminescence spectra show the evolution of defect exciton upon hydrogenation, which behaves differently from that of free excitons. Time-resolved photoluminescence measurement further reveals the change of defect-induced exciton dynamics in monolayer TMDs after hydrogenation process. Based on the experimental observations, we propose a microscopic picture for the hydrogenation process in monolayer TMDs. Our work thus demonstrated the ability to tune the defect emission and gained the knowledge of structural defects in monolayer TMDs.