Designing high-efficiency electrode contacts to two-dimensional semiconductor Cu2Se

[Display omitted] •Cu2Se/T-VS2, Cu2Se/H-TaSe2, and Cu2Se/H-NbSe2 vdWHs gain Ohmic contacts and low tunneling barriers simultaneously.•The origin of the Fermi pinning effect in our system is mainly due to interfacial dipoles.•H-NbSe2 is screened out as the most adaptable electrode for monolayer Cu2Se. 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 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.