Computational identification of single-layer CdO for electronic and optical applications

The search for single-layer materials is an active research field. Using a first-principles design approach focusing on formation energy and bandgap, we search the family of II-VI oxides for metastable single-layer semiconductor materials. We discover a single-layer CdO phase that exhibits a small formation energy and a direct bandgap of 2.1 eV. The phonon spectrum confirms the dynamical stability of single-layer CdO. Calculations of the optical properties show a similar absorption to that of graphene. Estimates of the tunneling barrier of a graphene/CdO/graphene heterostructure reveal that CdO might be a potential dielectric for applications of graphene in electronic devices.