• 文献标题:   Uncovering the Evolution of Low-Energy Plasmons in Nanopatterned Aluminum Plasmonics on Graphene
  • 文献类型:   Article
  • 作  者:   ELIBOL K, VAN AKEN PA
  • 作者关键词:   chargetransfer plasmon, localized surface plasmon, electron energyloss spectroscopy, nanofabrication, graphene, scanning transmission electron microscopy
  • 出版物名称:   NANO LETTERS
  • ISSN:   1530-6984 EI 1530-6992
  • 通讯作者地址:  
  • 被引频次:   2
  • DOI:   10.1021/acs.nanolett.2c01512 EA JUL 2022
  • 出版年:   2022

▎ 摘  要

We report adjusting the charge-transfer-plasmon (CTP) resonances of aluminum (Al) bowties on suspended monolayer graphene via controlled nanofabrication and focused electron-beam irradiation. CTP resonances of bowties with a conductive junction blue-shift with an increase in junction width, whereas their 3 lambda/2 and lambda resonances barely red-shift. These plasmon modes are derived and confirmed by an LC circuit model and electromagnetic simulations performed with boundary-element and frequency-domain methods. A monotonic decay of the CTP lifetime is observed, while the junction width is extended. Instead, the lifetimes of 3 lambda/2 and lambda resonances are nearly independent of junction width. When the junction is shrunk by electron-beam irradiation, all antenna resonances red-shift. Having created an electron-beam-induced sub 5 nm gap in bowties, we monitor the unambiguous transition of a CTP into a bonding-type gap mode, which is highly sensitive to the separation distance. Meanwhile, the 3 lambda/2 and lambda resonances evolve into dipolar bright and dipolar dark modes.