Defect-induced conductivity anisotropy in MoS 2 monolayers

Various types of defects in MoS2 monolayers and their influence on the electronic structure and transport properties have been studied using the density-functional-based tight-binding method in conjunction with the Green's function approach. Intrinsic defects in MoS2 monolayers significantly affect their electronic properties. Even at low concentration they considerably alter the quantum conductance. While the electron transport is practically isotropic in pristine MoS2, strong anisotropy is observed in the presence of defects. Localized midgap states are observed in semiconducting MoS2 that do not contribute to the conductivity but direction-dependent scatter the current, and that the conductivity is strongly reduced across line defects and selected grain boundary models.