Theoretical investigation on carrier mobilities of armchair graphene nanoribbons with substituted edges

Highlights: • Edge substitutions of armchair graphene nanoribbons are investigated theoretically. • Activating groups decrease the deformation potential constant. • Activating groups greatly increase the major carrier mobilities. • Modified frontier crystal orbitals explain the increment of the carrier mobilities. - Abstract: Armchair graphene nanoribbons with several substituent groups (–OH, –NH₂, –NO₂, –CN and –Cl) present on the edges are investigated by using crystal orbital method based on density functional theory. It is indicated that substituting half of the edge hydrogen atoms does not significantly change the frontier band structures of the graphene nanoribbons. However, the carrier mobilities obtained from deformation potential theory are significantly modified. Activating groups especially for hydroxyl groups can greatly increase the major carrier mobilities, while deactivating groups decrease them. These can be explained by the modified frontier crystal orbitals caused by the substituent groups