Electronic and Transport Properties in Defective MoS2: Impact of Sulfur Vacancies

Crystal impurities, such as atomic vacancies, are known to modulate the charge transport characteristics of two-dimensional (2D) materials. Here, we apply a first-principles-enriched tight-binding modelling approach to assess the influence of sulfur vacancies on the electronic structure and quantum transport characteristics of MoS2 monolayers. To this end, an sp(3)d(5) orthogonal tight-binding (oTB) model of the pristine and defective MoS2 monolayer is mapped with electronic structure calculations performed at the density functional theory level and subsequently used in the real-space Kubo-Greenwood (KG) scheme for charge transport simulations. The calculated charge carrier mobility is found to be sensitive to both the density and spatial arrangement of vacancies. Our oTB/KG simulations predict a drop of mobility by two orders of magnitude when the vacancy concentration is increased from 0.1 to 3%, in excellent agreement with experimental results. The simulation of realistic samples (including specific types of defects) pave a new route toward the accurate understanding and the possible prediction of 2D materials for nanoelectronic devices.