van der Waals Force: A Dominant Factor for Reactivity of Graphene

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• 作者：Jong Hak Lee ; Ahmet Avsar ; Jeil Jung ; Jun You Tan ; K. Watanabe ; T. Taniguchi ; Srinivasan Natarajan ; Goki Eda ; Shaffique Adam ; Antonio H. Castro Neto ; Barbaros 脰zyilmaz
• 刊名：Nano Letters
• 出版年：2015
• 出版时间：January 14, 2015
• 年：2015
• 卷：15
• 期：1
• 页码：319-325
• 全文大小：467K
• ISSN：1530-6992

文摘

Reactivity control of graphene is an important issue because chemical functionalization can modulate graphene鈥檚 unique mechanical, optical, and electronic properties. Using systematic optical studies, we demonstrate that van der Waals interaction is the dominant factor for the chemical reactivity of graphene on two-dimensional (2D) heterostructures. A significant enhancement in the chemical stability of graphene is achieved by replacing the common SiO₂ substrate with 2D crystals such as an additional graphene layer, WS₂, MoS₂, or h-BN. Our theoretical and experimental results show that its origin is a strong van der Waals interaction between the graphene layer and the 2D substrate. This results in a high resistive force on graphene toward geometric lattice deformation. We also demonstrate that the chemical reactivity of graphene can be controlled by the relative lattice orientation with respect to the substrates and thus can be used for a wide range of applications including hydrogen storage.