First-principles calculations of electronic properties for Edge-Modified Graphene Nanoribbons

Zigzag graphene nanoribbons with edges modified by different chemical groups are investigated by first principles calculations. The chemical groups considered include hydrogen, hydroxyl, ketone, and combination of hydrogen and hydroxyl. Band structures. DOS and charge difference density have been calculated. The results show that, the effect of different groups could be essentially ascribed to different types of edge. The structures of sp² type have little influence on electron state of the inner atoms of GNRs whose metallicity still remains. However the structures of sp³ type generate a band gap which will decrease with the increase of ribbon's width. The shift from metallicity to semiconducting occurs in both structures of GNRs-H₂ and GNRs-H₂O, while the structure of GNRs-O remains its metallicity as its Fermi level increases into the conduction band. By using this method of edge hybridization, the GNRs' band structure is prone to be controlled. (authors)