Characterization of the metal/MoS₂ top contact based on first-principles quantum transport calculations

We have recently reported the experimental achievement of Ohmic van der Waals (vdW) contacts at the indium (In)/MoS₂ devices thorough a novel thermal evaporation process, and based on the combined density functional theory and matrix Green’s function calculations concluded that the nature of the ideal Ohmic contact is characterized by the abrupt and rigid shift of TMDC bands across the In/MoS₂ interface (i.e. no band bending) together with the formation of metal-induced gap states (MIGS) [1]. In this work, we extend the analysis by considering four other metal species, Ag, Au, Sc, and Pd. Systematically considering how the electrode contact-region MoS₂ electronic structure develops into that of the channel region in different metal cases, we conclude that the identification of MIGS (rather than band bending) as the main determining factor for the clean metal/MoS₂ contacts is generally valid irrespective of the differences in the metal work function and wettability.
[1] B. K. Kim, D. H. Kim, and T. H. Kim et al. arXiv:1904.10295 [cond-mat.mes-hall]