Designing High-Efficiency Electrode Contacts to Two-Dimensional Semiconductor Cu₂Se

Abstract

High-efficiency electrode contact plays a pivotal role in achieving 2D material-based high performance nano devices. Recently, monolayer semiconducting Cu₂Se with high stability in air and high carrier mobility of about 10³ cm² V−1 s−1 have been experimentally fabricated. Herein, to design high-efficiency electrode contacts for Cu₂Se monolayer, the contact properties between Cu₂Se monolayer and a series of experimentally fabricated 2D metals (MX₂ in T-phase or H-phase, M = Ni, Nb, Ti, V, Co, Zr, and Ta, X = S, Se and Te) are systematically investigated based on first-principles calculations. Considering both Schottky barriers and tunneling barriers of these metal-semiconductor junctions (MSJs), H-NbSe₂ is screened out as the most adaptable electrode for monolayer Cu₂Se. Moreover, the weak fermi level pinning effects are discovered in these MSJs due to the potential steps contributed by the interface dipoles. Our work not only provides useful instruction for the design of high-performance 2D nano devices based on Cu₂Se monolayer but also offers insights for prospection into the fundamental electronic properties of MSJs.

Keywords: metal-semiconductor junctions, Schottky barrier, tunneling barrier