Interfacial Properties for a Monolayer CrS 2 Contact with Metal: A Theoretical Perspective

Limited calculations show that monolayer (ML) chromium dichalcogenide (CrS 2 ) has a direct bandgap and valley polarization but with a smaller bandgap than ML MoS 2 and with distinct piezoelectric and ferromagnetic properties. It is highly desirable to determine an appropriate metal contact for novel two‐dimensional (2D) CrS 2 ‐based devices. By using density functional theory (DFT), the interface between ML CrS 2 and commonly used metals, including s ‐electron and d ‐electron metals, is studied systematically by evaluating the binding energy, Schottky barrier, orbital overlap, and tunneling barrier at the interfaces. The d ‐electron metals show higher binding energy with the ML CrS 2 than the s ‐electron metals, which is due to the different occupancy and position of the d ‐band of the metals. A strong Fermi level pinning is found in the metal–CrS 2 contacts. Both n‐type and quasi p‐type phenomena for CrS 2 with respect to pristine CrS 2 can be produced at the CrS 2 contacts with the metals. The higher overlap states between the CrS 2 and Ti result in a higher minimum electron density at the Schottky interface, suggesting that Ti is the best contact among the investigated metals for use in CrS 2 ‐based devices for efficient electron injection. The DFT results provide a guideline that is invaluable for experimentally designing novel 2D CrS 2 semiconductor devices.