Controllable vdW Contacts between the Ferroelectric In₂Se₃ Monolayer and Two-Dimensional Metals

Developing low dimensional multifunctional devices becomes more and more important as the scale of the field-effect transistors decreases. Although van der Waals (vdW) contacts between two-dimensional semiconductors and metals have shown great potential, direct control of the performance of such contacts has still not been explored. Here, we predicted that vdW contacts between ferroelectric semiconductors and metals can present multifunctional performances switched by an external electric field. Based on first-principles calculations, our results shown that when the polarization direction of In₂Se₃ is reversed from downward to upward, the original n-type Schottky contact turned out to be the highly desirable ohmic contact in In₂Se₃/M₃C₂(M= Zn, Cd, Hg), while a transition from the p-type to n-type Schottky contact is observed in VS₂ and TSe₂ (T = V, Nb, Ta) metals. The calculated pinning factors suggest a weak Fermi-level pinning effect and tunable Schottky barrier height. Thus, our results show the strong effect of ferroelectric polarization on the properties of vdW contacts, which is important for designing and fabricating high-performance field-effect transistors.