Xiaowei Zhang, Oleg V. Yazyev, Juanjuan Feng, Liming Xie, Chenggang Tao, Yen-Chia Chen, Liying Jiao, Zahra Pedramrazi, Alex Zettl, Steven G. Louie, Hongjie Dai, Michael F. Crommie
The edges of graphene nanoribbons (GNRs) have attracted much interest due to their potentially strong influence on GNR electronic and magnetic properties. Here we report the ability to control the microscopic edge termination of high quality GNRs via hydrogen plasma etching. Using a combination of high-resolution scanning tunneling microscopy and first-principles calculations, we have determined the exact atomic structure of plasma-etched GNR edges and established the chemical nature of terminating functional groups for zigzag, armchair and chiral edge orientations. We find that the edges of hydrogen-plasma-etched GNRs are generally free of structural reconstructions and are terminated by hydrogen atoms with no rehybridization of the outermost carbon edge atoms. Both zigzag and chiral edges show the presence of edge states.
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http://arxiv.org/abs/1205.3516
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