Effect of Vacancy Defects and Strain on the Electronic Properties of Monolayer MoS2

Abstract

The electronic properties of the MoS₂ system under five different types of defects and biaxial compressive strain were investigated using first-principles calculations based on density functional theory (DFT). The results revealed that introduction of the defect transformed the MoS₂ system from direct band gap semiconductor to indirect band gap semiconductor. Among the five investigated defects, V_s vacancy defect exhibited the lowest formation energy. When biaxial compressive strain was applied to pristine and defective MoS₂ systems, the band gap decreased with increasing strain. Especially, the V_Mo vacancy defect system underwent a semiconductor to metal transition at approximately 6% compressive strain. This study provides theoretical insights into defect engineering and strain modulation strategies for optimizing the electronic properties of transition metal dichalcogenides.