Understanding the plasmonics of nanostructured atomic force microscopy tips
Applied Physics Letters
American Institute of Physics
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Sanders, A., Bowman, R., Zhang, L., Turek, V., Sigle, D., Lombardi, A., Weller, L., & et al. (2016). Understanding the plasmonics of nanostructured atomic force microscopy tips. Applied Physics Letters, 109 (15. 153110)https://doi.org/10.1063/1.4964601
Structured metallic tips are increasingly important for optical spectroscopies such as tip-enhanced Raman spectroscopy, with plasmonic resonances frequently cited as a mechanism for electric field enhancement. We probe the local optical response of sharp and spherical-tipped atomic force microscopy (AFM) tips using a scanning hyperspectral imaging technique to identify the plasmonic behaviour. Localised surface plasmon resonances which radiatively couple with far-field light are found only for spherical AFM tips, with little response for sharp AFM tips, in agreement with numerical simulations of the near-field response. The precise tip geometry is thus crucial for plasmon-enhanced spectroscopies, and the typical sharp cones are not preferred.
Is supplemented by: https://doi.org/10.17863/CAM.4682
The authors thank EPSRC Grant Nos. EP/G060649/1, EP/K028510/1, and EP/L027151/1, and ERC Grant No. LINASS 320503 for funding and NanoTools for their services providing Au-coated spherical AFM tips. R.W.B. thanks Queens' College and the Royal Commission for the Exhibition of 1851 for financial support.
European Research Council (320503)
External DOI: https://doi.org/10.1063/1.4964601
This record's URL: https://www.repository.cam.ac.uk/handle/1810/261287