Line Defects in Molybdenum Disulfide Layers

Abstract

Layered\nmolecular materials and especially MoS₂ are\nalready accepted as promising candidates for nanoelectronics. In contrast\nto the bulk material, the observed electron mobility in single-layer\nMoS₂ is unexpectedly low. Here we reveal the occurrence\nof intrinsic defects in MoS₂ layers, known as inversion\ndomains, where the layer changes its direction through a line defect.\nThe line defects are observed experimentally by atomic resolution\nTEM. The structures were modeled and the stability and electronic\nproperties of the defects were calculated using quantum-mechanical\ncalculations based on the Density-Functional Tight-Binding method.\nThe results of these calculations indicate the occurrence of new states\nwithin the band gap of the semiconducting MoS₂. The most\nstable nonstoichiometric defect structures are observed experimentally,\none of which contains metallic Mo–Mo bonds and another one\nbridging S atoms.