Defect Engineering in MoS₂ Monolayers on Au(111): Insights from Combined Experimental and Theoretical Approaches

In this study, we present a combined experimental and theoretical study of point defects in MoS₂ monolayers supported on Au(111). By tuning the experimental conditions, we achieved selective defect formation, paving the way for advanced defect engineering. Density functional theory (DFT) simulations were performed to model both the perfect Moiré superstructure and a variety of defect configurations. This allowed us to precisely identify the experimentally created single- and multiatom vacancies, interpret their contrast in scanning tunneling microscopy (STM), and characterize their electronic properties and effects on the valence band (VB). Our results show that tuning the kinetics of ion bombardment and the chemical environment during annealing treatments can produce different combinations of simple and complex defects. Additionally, we find that the Moiré modulation has minimal impact on the geometric and electronic properties of the surface, suggesting that the defect-engineered MoS₂/Au surface could serve as a rather general model system to further investigate the electronic and catalytic properties of MoS₂-based nanomaterials.