Monitoring Morphological Changes in 2D Monolayer Semiconductors Using Atom-Thick Plasmonic Nanocavities
Sigle, Daniel O
Herrmann, Lars O
Yang, Hui Ying
American Chemical Society
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Sigle, D. O., Mertens, J., Herrmann, L. O., Bowman, R., Ithurria, S., Dubertret, B., Shi, Y., et al. (2014). Monitoring Morphological Changes in 2D Monolayer Semiconductors Using Atom-Thick Plasmonic Nanocavities. ACS Nano, 9 825-830. https://doi.org/10.1021/nn5064198
Nanometre-sized gaps between plasmonically-coupled adjacent metal nanoparticles enclose extremely-localised optical fields which are strongly enhanced. This enables the dynamic investigation of nanoscopic amounts of material in the gap using optical interrogation. Here we use impinging light to directly tune the optical resonances inside the plasmonic nanocavity formed between single gold nanoparticles and a gold surface, filled with only yoctograms of semiconductor. The gold faces are separated by either monolayers of molybdenum disulphide (MoS_2) or two-unit-cell thick cadmium selenide (CdSe) nanoplatelets. This extreme confinement produces modes with hundred-fold compressed wavelength, which are exquisitely sensitive to morphology. Infrared scattering spectroscopy reveals how such nanoparticle-on-mirror modes directly trace atomic-scale changes in real time. Instabilities observed in the facets are crucial for applications such as heat-assisted magnetic recording that demand long-lifetime nanoscale plasmonic structures, but the spectral sensitivity also allows directly tracking photochemical reactions in these 2-dimensional solids.
Tunable plasmons, 2D-materials, molybdenum disulphide, waveguides, nanoparticles, nano-optics
This work was supported by the UK EPSRC grant EP/G060649/1, Defence Science and Technology Laboratory (DSTL), and ERC grant 320503 LINASS.
European Research Council (320503)
External DOI: https://doi.org/10.1021/nn5064198
This record's URL: https://www.repository.cam.ac.uk/handle/1810/247137
Creative Commons Attribution 4.0
Licence URL: http://creativecommons.org/licenses/by/4.0/