Electronic Properties of Graphene Altered by Substrate Surface Chemistry and Externally Applied Electric Field

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• 作者：Kun Chen ; Xiaomu Wang ; Jian-Bin Xu ; Lijia Pan ; Xinran Wang ; Yi Shi
• 刊名：The Journal of Physical Chemistry C
• 出版年：2012
• 出版时间：March 15, 2012
• 年：2012
• 卷：116
• 期：10
• 页码：6259-6267
• 全文大小：597K
• 年卷期：v.116,no.10(March 15, 2012)
• ISSN：1932-7455

文摘

The electronic properties of graphene supported by the (0001) SiO₂ surface are theoretically studied using density functional theory. It is found that the electronic attributes of graphene on (0001) SiO₂ strongly depend on the underlying SiO₂ surface properties and the percentage of hydrogen passivation. By applying methyl to passivate the oxygen-terminated (0001) SiO₂ surface, one can further reduce the interaction between the graphene sheet and oxygen-terminated surface. This can improve the charge carrier mobility of graphene supported by SiO₂ substrate and reduce the influence of residues of interfacial molecules. In addition, the external electric field modulates the charge transfer between graphene and the SiO₂ surface when graphene layers are physisorbed on the oxide surface. This phenomenon will enhance the built-in electric field of bilayer graphene so as to effectively modify its band structure. Our results shed light on a better atomistic understanding of the recent experiments on graphene supported by SiO₂.