In Situ Observation of Electrostatic and Thermal Manipulation of Suspended Graphene Membranes

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• 作者：Wenzhong Bao ; Kevin Myhro ; Zeng Zhao ; Zhen Chen ; Wanyoung Jang ; Lei Jing ; Feng Miao ; Hang Zhang ; Chris Dames ; Chun Ning Lau
• 刊名：Nano Letters
• 出版年：2012
• 出版时间：November 14, 2012
• 年：2012
• 卷：12
• 期：11
• 页码：5470-5474
• 全文大小：320K
• 年卷期：v.12,no.11(November 14, 2012)
• ISSN：1530-6992

文摘

Graphene is nature鈥檚 thinnest elastic membrane, and its morphology has important impacts on its electrical, mechanical, and electromechanical properties. Here we report manipulation of the morphology of suspended graphene via electrostatic and thermal control. By measuring the out-of-plane deflection as a function of applied gate voltage and number of layers, we show that graphene adopts a parabolic profile at large gate voltages with inhomogeneous distribution of charge density and strain. Unclamped graphene sheets slide into the trench under tension; for doubly clamped devices, the results are well-accounted for by membrane deflection with effective Young鈥檚 modulus E = 1.1 TPa. Upon cooling to 100 K, we observe buckling-induced ripples in the central portion and large upward buckling of the free edges, which arises from graphene鈥檚 large negative thermal expansion coefficient.

Keywords:

Graphene; in situ SEM imaging; deflection; buckling; sliding; thermal expansion