NbS 2 : A Promising p -Type Ohmic Contact for Two-Dimensional Materials

Although two-dimensional (2D) semiconductors are the focus for next-generation field-effect transistors, it is still difficult to produce good, simple electrical contacts with these materials. The authors use density functional theory to study the Schottky-barrier height under the influence of a vertical external electric field, and demonstrate that NbS${}_{2}$ is a promising electrode for achieving $p$-type Ohmic contact with WSe${}_{2}$ and BP monolayers, with trivial dependence on external field. This suggests that with metallic NbS${}_{2}$ monolayer as the electrode, the influence of gate voltage on electrode-channel interfaces can be greatly suppressed, which has real impact on circuit design.