Ab-Initio Transport Study of Source-to-Channel Resistance in Metal-MoS ${ }_{2}$ Top Contacts Including Image Force Barrier Lowering in a Heterogeneous Dielectric Environment

We present an ab-inito transport study, based on the Density Functional Theory (DFT) and the non-equilibrium Green's Functions (NEGF) formalism, to assess the effect of the Image Force Barrier Lowering (IFBL) on the source-tochannel resistance (<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$R_{\mathbf{C}}$</tex>) in metal-MoS<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> top contacts. To compute the IFBL potential profile, our model relies on the numerical solution of the 3D Poisson equation for the point charge in a heterogeneous dielectric environment. By considering Al-MoS<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> and Bi-MoS<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> van-der-Waals heterojunctions, representative of a Schottky and an Ohmic contact respectively, we show that, while for Schottky contacts the inclusion of the IFBL has a vast impact on the source-to-channel resistance, in quasi-Ohmic contacts the influence of the IFBL on the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$R_{\mathbf{C}}$</tex> becomes negligible, especially at large inversion densities.