The Modifications of Electronic and Optical Properties of Bulk Molybdenum Disulfide by Oxygen Substitution

Abstract

We study the electronic and optical properties of bulk MoS2 and MoSO systems using the plane-wave method within the generalized gradient approximation. The structural properties show that the O substitution at S sites tunes the z-axis Wyckoff positions of all atoms and the bond angles. The electronic band structures show that the substitution tunes the conduction band minimum at 0.8 Σ to M and significantly promotes more localized valence states compared to that of MoS2 system. The localization, mainly applying to Mo 4d and S 3p states, is more pronounced above −4 eV. Below −4 eV, O 2p states are dominant indicating that they are more stable than S 3p states. However, the substitution slightly increases the indirect and direct (K → K) bandgap of MoS2 system. From the optical properties, both systems show the strong optical dichroism. By means of the substitution, the σ1 width significantly enhances, while the plasmonic-state energy levels decrease. Our result emphasizes that the O substitution significantly tunes the electronic and optical properties of bulk MoS2 system.