Interfacial contact barrier and charge carrier transport of MoS/metal(001) heterostructures.

The rapid rise of two-dimensional (2D) materials has aroused increasing interest in the fields of microelectronics and optoelectronics; various types of 2D van der Waals heterostructures (vdWHs), especially those based on MoS, have been widely investigated in theory and experiment. However, the interfacial properties of MoS and the uncommon crystal surface of traditional three-dimensional (3D) metals are yet to be explored. In this paper, we studied heterostructures composed of MoS and metal(001) slabs, based on the first-principles calculations, and we uncovered that MoS/Au(001) and MoS/Ag(001) vdWHs reveal Schottky contacts, and MoS/Cu(001) belongs to Ohmic contact and possesses ultrahigh electron tunneling probability at the equilibrium distance. Thus, the MoS/Cu(001) heterostructure exhibits the best contact performance. Further investigations demonstrate that external longitudinal strain can modulate interfacial contact to engineer the Schottky-Ohmic contact transition and regulate interfacial charge transport. We believe that it is a general strategy to exploit longitudinal strain to improve interfacial contact performance to design and fabricate a multifunctional MoS-based electronic device.