周期性纳米洞内边缘氧饱和石墨烯纳米带的电子特性

Electronic properties of graphene nanoribbons with periodical nanoholes passivated by oxygen

利用基于密度泛函理论的第一性原理方法,研究了内边缘氧饱和的周期性凿洞石墨烯纳米带(G NR)的电子特性.研究结果表明:对于凿洞锯齿形石墨烯纳米带(ZGNRs),在非磁性态时不仅始终为金属,且金属性明显增强;反铁磁态(AFM)时为半导体的ZGNR,凿洞后可能成为金属;但铁磁态(FM)为金属的ZGNR,凿洞后一般变为半导体或半金属.而对于凿洞的扶手椅形石墨烯(AGNRs),其带隙会明显增加.深入分析发现:这是由于氧原子对石墨烯纳米带边的电子特性有重要的影响,以及颈次级纳米带(NSNR)及边缘次级纳米带(ESNR)的不同宽度及边缘形状(锯齿或扶手椅形)能呈现出不同的量子限域效应.这些研究对于发展纳米电子器件有重要的意义.

By using the first-principles method and the density-functional theory, the electronic properties of graphene nanoribbons（GNRs） with periodic nanoholes passivated by oxygen are studied. It is shown that for the zigzag graphene nanoribbon （ZGNR） in nonmagnetic state（NM）, the metallic properties not only still remain but also are obviously enhanced after the holes are punched. But for the antiferromagnetic-state （AFM） ZGNR, after punching holes, it would be changed from semiconductor to metal. While for the ferromagnetic-state （FM） ZGNR, it can be transformed from metal to semiconductor or semimetal after punching holes. Besides, for the punched armchair graphene nanoribbon （AGNR）, its band gap will be significantly widened. The in-depth analysis shows that these results are due to the effects of oxygen atoms on electronic properties of GNRs, and also due to the different quantum confinement effects from the neck subprime nanoribbon （NSNR） and edge subprime nanoribbon （ESNR） with different width and edge shape（zigzag or armchair）. These findings are important for developing nano electronic devices.