Interfacial Properties of Monolayer Antimonene Devices

As an emerging stable two-dimensional (2D) semiconductor, monolayer (ML) antimonene is of great interest for future electronic and optoelectronic device applications. However, correlative research has been hindered by the lack of high-quality electrode contact. In this paper, on the basis of ab initio electronic calculations and quantum-transport simulations, the interfacial contact properties of ML antimonene-metal contacts are studied comprehensively for the first time. ML antimonene forms n-type Schottky contacts with Sc, Cr, and Ti electrodes, with an electron Schottky-barrier height (SBH) of 0.44, 0.49, and 0.52 eV, respectively, while it forms a p-type Schottky contact with Ag, bulk Sb, Au, Pt, and Pd, with a hole SBH of 0.56, 0.44, 0.4, 0.31, and 0.29 eV, respectively. The Fermi pinning factor S is calculated to be 0.29, indicating a strong pinning effect. By contact with graphene or 2D Hf2N(OH)2 or by insertion of monolayer BN or graphene between ML antimonene and bulk metal, the Fermi-level pinning effect can be weakened because of the suppression of metal-induced gap states. ML antimonene forms a p-type contact with graphene with a small lateral hole SBH of 0.12 eV. In a ML antimonene device with 2D Hf2N(OH)2 and graphene-Pt as electrodes n-type Ohmic contact and p-type Ohmic contact are realized, respectively, indicative of a potentially high device performance. Our study provides a theoretical basis for the selection of favorable electrodes in future ML antimonene devices. Namely, the optimal n-type electrode is 2D Hf2N(OH)2, followed by Sc, Cr, and Ti electrodes, and the optimal p-type electrode is graphene-Pt or graphene, followed by Pd, Pt, Au, bulk Sb, and Ag electrodes.