Dresden 2017 – scientific programme

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DS: Fachverband Dünne Schichten

DS 44: Postersession II

DS 44.46: Poster

Thursday, March 23, 2017, 17:00–19:00, P1C

Introducing band gap states in MoS₂ monolayers by triangular defects — Tommy Lorenz¹, •André Niebur^1,2, Sibylle Gemming^2,3, Artur Erbe², and Gotthard Seifert¹ — ¹Theoretical Chemistry, TU Dresden, 01062 Dresden, Germany — ²Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden - Rossendorf e.V., 01314 Dresden, Germany — ³Theoretical Physics, Faculty of Sciences, TU Chemnitz, 09107 Chemnitz, Germany

Triangular defects in MoS₂ monolayers and their influence on the crystal and electronic structure have been studied using the density-functional based tight-binding (DFTB) method. Systems with different defect sizes and concentrations have been compared to find out how these parameters affect the electronic properties of MoS₂ monolayers. The density of states (DOS) calculations show the presence of additional states in the HOCO-LUCO-Gap of pristine MoS₂ even for small defects in a low concentration. Band structure calculations and orbital plots characterize these states as localized mid-gap states. From the projected densities of states can be seen that these states mainly arise from d-orbitals of the molybdenum atoms at the defect edges and their number increases with an increasing defect size. Due to the fact that the molybdenum d-states dominate the valence and conduction band edges of MoS₂, the additional states which arise in the band gap may impact the electronic transport through the layer. Analyses of the orbital’s degree of (de-) localization show that this influence seems to be quite small for low defect concentrations but increases for higher ones.