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Transport Properties of Zigzag Graphene Nanoribbons Decorated by Carboxyl Group Chains

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journal contribution
posted on 10.11.2011, 00:00 authored by C. X. Zhang, Chaoyu He, Zhizhou Yu, K. W. Zhang, L. Z. Sun, Jianxin Zhong
The transport properties of zigzag graphene nanoribbons (ZGNRs) decorated by carboxyl group (OH) chains are systematically investigated using the density functional theory in combination with the nonequilibrium Green’s function method. ZGNRs with nine zigzag carbon chains (9ZGNR) decorated by mOH (m is the number of oxidized carbon chains) are taken as typical systems. We find that the OH chains can effectively modulate the electronic structures and transport properties of the 9ZGNR. The systems behave as metal when m ≤ 4, and a transmission plateau up to 6G0 is found around the Fermi level when m = 3. However, when m > 4, the 9ZGNR-mOH systems become semiconductors. Interestingly, 9ZGNR-7OH and 9ZGNR-8OH behave as n-type semiconductors. It is found that such modulation depends on the edge states as well as the oxygen atoms at the interface. When the width of undecorated carbon regions is <3, Peierls instability induces the metal–semiconductor transition.