Ultraconfined Plasmonic Hotspots Inside Graphene Nanobubbles
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- 作者：Z. Fei ; J. J. Foley IV ; W. Gannett ; M. K. Liu ; S. Dai ; G. X. Ni ; A. Zettl ; M. M. Fogler ; G. P. Wiederrecht ; S. K. Gray ; D. N. Basov
- 刊名：Nano Letters
- 出版年：2016
- 出版时间：December 14, 2016
- 年：2016
- 卷：16
- 期：12
- 页码：7842-7848
- 全文大小：518K
- ISSN：1530-6992
文摘
We report on a nanoinfrared (IR) imaging study of ultraconfined plasmonic hotspots inside graphene nanobubbles formed in graphene/hexagonal boron nitride (hBN) heterostructures. The volume of these plasmonic hotspots is more than one-million-times smaller than what could be achieved by free-space IR photons, and their real-space distributions are controlled by the sizes and shapes of the nanobubbles. Theoretical analysis indicates that the observed plasmonic hotspots are formed due to a significant increase of the local plasmon wavelength in the nanobubble regions. Such an increase is attributed to the high sensitivity of graphene plasmons to its dielectric environment. Our work presents a novel scheme for plasmonic hotspot formation and sheds light on future applications of graphene nanobubbles for plasmon-enhanced IR spectroscopy.