Planar Direction‐Dependent Interfacial Properties in Monolayer In 2 Se 3 –Metal Contacts

2D semiconductor materials are promising channel materials in the next generation of field-effect transistors (FETs). Recently, 2D In2Se3 has been fabricated and predicted to present planar direction-dependent electrical properties. Herein, ab initio quantum transport simulations are used to explore the interfacial properties between monolayer (ML) In2Se3 and a series of common metal electrodes in a FET. By reversing the planar direction of ML In2Se3, different lateral interfacial properties are obtained: A highly desirable n-type ohmic contact is shaped between Au and up-directed ML In2Se3; however, a p-type Schottky contact appears when the direction is switched. In addition, Ag can generate desirable lateral n-type ohmic contact with both the directions of ML In2Se3. A reversion from n- to p-type lateral Schottky contact occurs in both In and Sc when the direction switches from up to down. Down-directed ML In2Se3 is dynamically unstable with the Pt and transforms into up-direction to form a p-type ohmic contact. The average pinning factor is 0.12 and 0.09 for up-and down-directed ML In2Se3, respectively, implying a strong Fermi-level pinning. Therefore, the planar direction-dependent interfacial properties of ML In2Se3–metal contacts are understood deeply, which can be exploited for the ML In2Se3 FET devices.