▎ 摘　　要

The exfoliation of graphene triggered dramatic interest to explore other two-dimensional materials for functionalizing future nanoelectronic devices. In this study, via first-principles calculations, we predict a stable planar Y2O3 (111) monolayer with a direct band gap of 3.96 eV. This high-kappa dielectric monolayer can be further stabilized by a graphene substrate. The interaction between the planar Y2O3 (111) monolayer and graphene is found to be weak and dominated by van der Waals interactions, while the electronic properties are determined by orbital hybridization and electrostatic interaction. Our results indicate that a high-kappa dielectric monolayer can be formed on a substrate with weak interfacial interaction via a physical deposition process, and this sheds light on engineering extremely thin high-kappa dielectrics on graphene-based electronics with desired properties.