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arXiv 1003.0853cond-mat.mes-hallcond-mat.mtrl-sci
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失配应变和基底表面波纹对支撑单层石墨烯形貌的影响

Effects of Mismatch Strain and Substrate Surface Corrugation on Morphology of Supported Monolayer Graphene

Zachary H. Aitken, Rui Huang

摘要:

氧化物衬底上的石墨烯单层已经被证明具有优异的电荷迁移率和热传输,用于潜在的器件应用。形貌的改变对石墨烯的输运性质有很大的影响。在本文中,我们从理论上分析了氧化物衬底上的石墨烯单层的形态稳定性,受到范德华相互作用和面内失配应变。首先,我们定义的平衡分离和界面粘附能作为两个关键参数,表征一个平坦的单层和一个平坦的基板表面之间的范德华相互作用。通过微扰分析,预测了临界压缩失配应变,超过该临界压缩失配应变,石墨烯单层经历应变诱导的不稳定性,在完全平坦的表面上形成具有增加的振幅和减小的波长的波纹。当衬底表面不完全平坦时,石墨烯的形态取决于表面反射的振幅和波长。预测从共形(波纹状)到非共形(平坦)形态的过渡。分析了衬底表面粗糙度对石墨烯平衡平均厚度和界面结合能的影响。此外,通过考虑衬底表面的应变和失配应变,人们发现,而拉伸失配应变降低石墨烯的应变幅度,波纹衬底表面促进应变诱导的不稳定性下的压缩应变。这些理论结果表明,通过表面图案化和应变工程来控制氧化物衬底上的石墨烯单层的形态的可能手段。

英文摘要:

Graphene monolayers supported on oxide substrates have been demonstrated with superior charge mobility and thermal transport for potential device applications. Morphological corrugation can strongly influence the transport properties of the supported graphene. In this paper, we theoretically analyze the morphological stability of a graphene monolayer on an oxide substrate, subject to van der Waals interactions and in-plane mismatch strains. First, we define the equilibrium separation and the interfacial adhesion energy as the two key parameters that characterize the van der Waals interaction between a flat monolayer and a flat substrate surface. By a perturbation analysis, a critical compressive mismatch strain is predicted, beyond which the graphene monolayer undergoes strain-induced instability, forming corrugations with increasing amplitude and decreasing wavelength on a perfectly flat surface. When the substrate surface is not perfectly flat, the morphology of graphene depends on both the amplitude and the wavelength of the surface corrugation. A transition from conformal (corrugated) to non-conformal (flat) morphology is predicted. The effects of substrate surface corrugation on the equilibrium mean thickness of the supported graphene and the interfacial adhesion energy are analyzed. Furthermore, by considering both the substrate surface corrugation and the mismatch strain, it is found that, while a tensile mismatch strain reduces the corrugation amplitude of graphene, a corrugated substrate surface promotes strain-induced instability under a compressive strain. These theoretical results suggest possible means to control the morphology of graphene monolayer on oxide substrates by surface patterning and strain engineering.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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