The Unusual Mechanism of Partial Fermi Level Pinning at Metal–MoS 2 Interfaces

Density functional theory calculations are performed to unravel the nature of the contact between metal electrodes and monolayer MoS2. Schottky barriers are shown to be present for a variety of metals with the work functions spanning over 4.2–6.1 eV. Except for the p-type Schottky contact with platinum, the Fermi levels in all of the studied metal–MoS2 complexes are situated above the midgap of MoS2. The mechanism of the Fermi level pinning at metal–MoS2 contact is shown to be unique for metal–2D-semiconductor interfaces, remarkably different from the well-known Bardeen pinning effect, metal-induced gap states, and defect/disorder induced gap states, which are applicable to traditional metal–semiconductor…