Oxygen atom adsorbed on the sulphur vacancy of monolayer MoS2: A promising method for the passivation of the vacancy defect

The properties of pristine monolayer MoS2, monolayer MoS2 with an S-vacancy, and monolayer MoS2 with an oxygen atom adsorbed on the S-vacancy are investigated by the first-principle method for different supercell sizes. For all defect concentrations, there are three gap states between the band gap for MoS2 with a S-vacancy that are expected to trap the carriers. The adsorption of an oxygen atom on the S-vacancy can remove these trapping gap states and eliminate that effect. The formation energies, electronic structures, and stresses under different biaxial tensile strains and Young’s modulus values are also calculated for both pristine and defective MoS2. The results of the pristine MoS2 and the MoS2 with an oxygen atom adsorbed on the S-vacancy are found to be similar, which indicates that the adsorption of an oxygen atom on the S-vacancy is a promising method for the passivation of the S-vacancy defect, even under tensile strain.