  A multiscale simulation approach is developed to simulate the contact
transport properties between semimetal to a monolayer two-dimensional (2D)
transition metal dichalcogenide (TMDC) semiconductor. The results elucidate the
mechanisms for low contact resistance between semimetal and TMDC semiconductor
contacts from a quantum transport perspective. The simulation results compare
favorably with recent experiments. Furthermore, the results show that the
contact resistance of a Bismuth-MoS2 contact can be further reduced by
engineering the dielectric environment and doping the TMDC material to <100
${\Omega}$.${\mu}$m. The quantum transport simulation indicates the possibility
to achieve an ultrashort contact transfer length of ~1 nm, which can allow
aggressive scaling of the contact size.
