▎ 摘　　要

Herein, a tight-binding description is utilized to investigate electronic structures and density of states of single-layer (SL) and bilayer (BL) graphene ribbons with and without the influence of external electric fields. Analyses are implemented to reveal the similarity and difference among electronic properties of three types of structures (specifically SL and BL ribbons with AA and AB stackings). Moreover, both armchair and zigzag edge orientations are considered. It is indicated in the results that variation in electronic properties of these structures in the presence of external electric fields depends on both structural form and edge orientation. The following two points are demonstrated: 1) a transverse field has a significant effect on adjusting bandgap of the zigzag configurations, whereas a vertical electric field has a distinct impact on energy bands of armchair edge structures, and 2) among considered structures, AB-stacking BL ribbons are invariably the structures that are most strongly influenced by external fields. Interestingly, AB-stacking BL ribbons are also capable of enlarging bandgap with both edge terminations. Herein, an insight into how the electronic structure and charge distribution of both SL and BL graphene nanoribbons can be controlled not only in armchair but also in zigzag edge terminations using electric stimulants is provided by the results.