Twisting Bilayer Graphene Superlattices

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• 作者：Chun-Chieh Lu ; Yung-Chang Lin ; Zheng Liu ; Chao-Hui Yeh ; Kazu Suenaga ; Po-Wen Chiu
• 刊名：ACS Nano
• 出版年：2013
• 出版时间：March 26, 2013
• 年：2013
• 卷：7
• 期：3
• 页码：2587-2594
• 全文大小：553K
• 年卷期：v.7,no.3(March 26, 2013)
• ISSN：1936-086X

文摘

Bilayer graphene is an intriguing material in that its electronic structure can be altered by changing the stacking order or the relative twist angle, yielding a new class of low-dimensional carbon system. Twisted bilayer graphene can be obtained by (i) thermal decomposition of SiC; (ii) chemical vapor deposition (CVD) on metal catalysts; (iii) folding graphene; or (iv) stacking graphene layers one atop the other, the latter of which suffers from interlayer contamination. Existing synthesis protocols, however, usually result in graphene with polycrystalline structures. The present study investigates bilayer graphene grown by ambient pressure CVD on polycrystalline Cu. Controlling the nucleation in early stage growth allows the constituent layers to form single hexagonal crystals. New Raman active modes are shown to result from the twist, with the angle determined by transmission electron microscopy. The successful growth of single-crystal bilayer graphene provides an attractive jumping-off point for systematic studies of interlayer coupling in misoriented few-layer graphene systems with well-defined geometry.

Keywords:

twisted bilayer graphene; single crystal; Raman; TEM