▎ 摘　　要

Field emission current density from the edge of graphene thin films is calculated in terms of their edge morphology, using density functional theory combined with the effective screening medium method and the Fowler-Nordheim theory. The field emission current from edges of the bilayer graphene is higher than that from the monolayer graphene edges. Edge displacement of the bilayer graphene causes a higher emission current than the aligned edges for both zigzag and armchair edges. Bilayer graphene with closed edges further enhances the emission current compared with those with open clean edges, owing to the decrease of their work functions and the potential barrier outside them. (C) 2019 Elsevier Ltd. All rights reserved.