DFT-NEGF transport in 2D channels with semimetal contacts: the influence of doping and bilayers

Using Density-Functional Theory and the Non-Equilibrium Green’s Function formalism, we investigate the fundamental transport mechanisms through Sb and Bi semimetal contacts with MoS
2
and WS
2
mono- and bilayer channels. Our results highlight low contact resistances below $200 \Omega \mu \mathrm{m}$ in monolayer systems, providing that a sufficiently high carrier concentration of $3 \times 10^{13} \mathrm{~cm}^{-2}$ is achieved, either through conventional or dynamical (electrostatic) doping. Contact resistances can be further lowered down to $50 \Omega \mu \mathrm{m}$ by using bilayers and the adequate type of doping.