Electronic and optical properties of S vacancy and Br and I doped monolayer MoS2: A first-principle study

This study investigated the energy band structure (BS), electronic state density, and optical properties of monolayer molybdenum disulfide (ML-MoS2) with undoped, sulfur vacancy (VS), bromine (Br), and iodine (I) doped MoS2 systems using the first-principle approach based on density functional theory (DFT). Our results show that compared to undoped MoS2 system, Br, and I doped MoS2 systems induced lattice distortions. In addition, and the bandgap widths was reduced in VS, Br, and I doped systems, thereby effectively suppressing the compounding of electron-hole pairs. Moreover, the recombination rate of electron-hole pairs was reduced, which in turn increased the mobility of electrons transferred from the valence band (VB) to the conduction band (CB). Moreover, the VS and Br doped systems exhibited superior optical properties compared to undoped MoS2 system. Notably, the VS system exhibited the best optical properties, thereby demonstrating the strongest polarization capability. Our findings pave the way for realizing electronic devices and photocatalytic materials on MoS2 nanostructures.