The electronic structure and interfacial contact with metallic borophene of monolayer ScSX (X = I, Br, and Cl)

Two-dimensional (2D) semiconductors with excellent electronic and optical properties provide a great prospect for the fundamental research and application for the next-generation devices. Exploring the contact properties between 2D semiconductors and metal electrodes for improving the performance of nanodevices is of utmost importance. Motivated by the successful synthesis of bulk ScSI experimentally in a recent work [A. M. Ferrenti, M. A. Siegler, S. Gao, N. Ng and T. M. McQueen, Chem. Mater., 2022, 34, 12, 5443–5451], here we systematically investigate the intrinsic structural, electronic and optical properties of the novel monolayer ScSX (X = I, Br, and Cl) and their interfacial contact properties with the metal electrode of borophene using first-principles calculations. Interestingly, halogen X atoms with different electronegativities not only influence the intrinsic properties of monolayer ScSX, but also affect the interlayer coupling between monolayer ScSX and metallic borophene. The ScSI/borophene heterostructure forms a p-type Schottky contact, while both ScSBr/borophene and ScSCl/borophene heterostructures form a n-type Schottky contact. Moreover, our calculations demonstrate that strain engineering and applying an external electric field are effective strategies to regulate the Schottky barrier and contact types at the interface of ScSX/borophene. These findings provide a very promising path for designing tunable Schottky nanodevices with high-performance based on monolayer ScSX.