Tuning The Electronic Properties Of Graphene Nanoribbon By Tailoring The Edge

Graphene has extremely high electron mobility and superior mechanical properties, which attracts more and more attention. Graphene nanoribbons could be semiconductors, which allows it to be a potential material for future nano-electronic devices. There are two types graphene nanoribbons based on the different atomic structure of the edges:zigzag graphene nanoribbons (ZGNRs) and armchair graphene nanoribbons (AGNRs). Both ZGNRs and AGNRs have semiconductor properties, and the band gap is inversely proportional to the width of the nanoribbons.In the preparation of graphene nanoribbons, various edge shapes are common, which will greatly influence the electronic and magnetic properties of graphene nanoribbons. Based on first-principle density functional theory calculations, we systematically studied the electronic and magnetic properties of ZGNRs and AGNRs with tailored edges. Our calculation results demonstrated that the electronic properties of ZGNRs and AGNRs are closely related with the edge shape. For ZGNRs with tailored V-shape defect on its edges, the band gap will decrease with the increase of V-shape density; while the band gap will increase with the increase of V-shape depth. By tailoring the single edge with a reasonable defect depth, the spin electronic states will be separated from each other. Based on this, we propose that spin semiconductors can be obtained by doping the single edge tailored ZGNRs with N-type or P-type atoms. For AGNRs, the band gap decreases with the increase of the tailoring density, and the band gap increases as the tailoring depth increases. The total magnetic moment of ZGNRs and AGNRs is proportional to the difference in the number of asymmetrical A, B carbon atoms. Tailoring can change the ferromagnetism of ZGNRs’ edges, and can make AGNRs with ferromagnetism. The current results could shed some lights on the future applications of graphene nanoribbons.