A Theoretical Investigation of Orientation-Dependent Transport in Monolayer MoS2 Transistors at the Ballistic Limit

Device performance of monolayer MoS₂ transistors is investigated by atomistic simulations within the non-equilibrium Green´s function formalism. A strong dependence of quantum transport on MoS2 orientation is predicted. To a large extent, the orientation dependence is due to subband transport properties and the atomistic structure along the transport direction. A bandgap is found in the conduction band along armchair direction (AD), which plays a major role for the orientation-dependent transport. At the same time, different atomic arrangements along AD and zigzag direction have different depletion region lengths, which also contribute to the orientation-dependent transport. Orientation dependence of drain current exists in MoS₂ FETs having different gate lengths.