Chemical and Electronic Repair Mechanism of Defects in MoS2 Monolayers

Using ab initio density functional theory cal- culations, we characterize changes in the elec- tronic structure of MoS2 monolayers introduced by missing or additional adsorbed sulfur atoms. We furthermore identify the chemical and elec- tronic function of substances that have been reported to reduce the adverse effect of sul- fur vacancies in quenching photoluminescence and reducing electronic conductance. We find that thiol-group containing molecules adsorbed at vacancy sites may re-insert missing sulfur atoms. And in the presence of sulfur adatoms, thiols may form disulfides on the MoS2 surface to mitigate the adverse effect of defects.