Ohmic MXene Contacts for Symmetric p- and n-type Monolayer WSe₂ Schottky Barrier Field-Effect Transistors

Achieving Ohmic-contact electrodes for two-dimensional (2D) Schottky barrier field-effect transistors (SBFETs) and symmetric p - and n -type performances are two pivotal aspects of 2D-based integrated circuits. As 2D WSe 2 possesses both high electron and hole mobilities, we choose monolayer (ML) WSe 2 as the channel and functionalized Nb 2 C with a similar lattice and a broad scope work function as the electrode. The contact properties and device performances are studied theoretically at the ab initio level. P - and n -type Ohmic contacts are achieved with high- and low-WF metals, i.e., Nb 2 CO 2 and Nb 2 C(OH) 2, respectively, and the interfaces are both clean without metal-induced gap states. The optimal ML WSe 2 SBFETs with Nb 2 CO 2 and Nb 2 C(OH) 2 electrodes possess symmetric p- and n -type I on values of 1542/1823 and 1688/2173 μA/μm, respectively, for low-power/high-performance (LP/HP) applications with a gate length of 3 nm and a supply voltage of 0.5 V, surpassing the International Roadmap for Device and Systems LP/HP target. This study suggested potential Ohmic-contact electrodes for symmetric p - and n -type ML WSe 2 SBFETs in the post-Si era.