TY - JOUR

T1 - Wavelength dependent gap-mode TERS by CdSe nanocrystals on a single Au nanodisk

AU - Milekhin, I. A.

AU - Rahaman, M.

AU - Tsarev, A. V.

AU - Anikin, K. V.

AU - Rodyakina, E. E.

AU - Duda, T. A.

AU - Saidzhonov, B. M.

AU - Vasiliev, R. B.

AU - Milekhin, A. G.

AU - Latyshev, A. V.

AU - Zahn, D. R.T.

N1 - The authors acknowledge the support from the Russian Science Foundation Grant No. 22-12-00302. The studies were performed using the equipment of Collective Use Center “Nanostructures”. The authors are grateful to L.A. Nenasheva and A.S. Medvedev for the TERS probes fabrication. We are very thankful to Dr. Niranjan Kumar for helpful discussions.

PY - 2024/12/25

Y1 - 2024/12/25

N2 - Tip-Enhanced Raman Scattering (TERS) is a powerful method for studying the local properties of nanomaterials. In the gap-mode TERS configuration, the object of investigation is placed in the gap between a TERS probe and a plasmonic nanostructure, it is possible to reach a dramatic increase in Raman sensitivity by choosing the excitation wavelength and plasmonic substrate. Here, we investigate the effect of the excitation wavelength on the TERS response from CdSe nanocrystals on a single Au nanodisk using the gap-mode TERS. For excitation wavelengths of 638.2 and 785.3 nm, the gap-mode TERS by CdSe phonon modes is significantly enhanced at nanodisk edges, forming a ring-like TERS pattern. The diameter of the TERS ring obtained for 638.2 nm amounts to 130 nm. In case of 785.3 nm, the TERS ring diameter increases up to 150 nm that corresponds to the Au nanodisk diameter, while the TERS signal is 12 times stronger than that for 638.2 nm. The calculation results of the near-field scattering from the hot spot, arising between the TERS probe apex and the Au nanodisk covered with a thin CdSe film, using the Finite-Difference Time-Domain method, explain the influence of the excitation wavelength on the TERS pattern variation.

AB - Tip-Enhanced Raman Scattering (TERS) is a powerful method for studying the local properties of nanomaterials. In the gap-mode TERS configuration, the object of investigation is placed in the gap between a TERS probe and a plasmonic nanostructure, it is possible to reach a dramatic increase in Raman sensitivity by choosing the excitation wavelength and plasmonic substrate. Here, we investigate the effect of the excitation wavelength on the TERS response from CdSe nanocrystals on a single Au nanodisk using the gap-mode TERS. For excitation wavelengths of 638.2 and 785.3 nm, the gap-mode TERS by CdSe phonon modes is significantly enhanced at nanodisk edges, forming a ring-like TERS pattern. The diameter of the TERS ring obtained for 638.2 nm amounts to 130 nm. In case of 785.3 nm, the TERS ring diameter increases up to 150 nm that corresponds to the Au nanodisk diameter, while the TERS signal is 12 times stronger than that for 638.2 nm. The calculation results of the near-field scattering from the hot spot, arising between the TERS probe apex and the Au nanodisk covered with a thin CdSe film, using the Finite-Difference Time-Domain method, explain the influence of the excitation wavelength on the TERS pattern variation.

KW - NCs

KW - Nanocrystals

KW - Plasmonic structures

KW - TERS

KW - Tip-enhanced Raman scattering

UR - https://www.scopus.com/record/display.uri?eid=2-s2.0-85213267104&origin=inward&txGid=2ca82556a20ec5c70bab93015c17210c

UR - https://www.mendeley.com/catalogue/3ee2e658-fbf0-3e5f-905b-f4e8808b54b7/

U2 - 10.1016/j.apsusc.2024.162144

DO - 10.1016/j.apsusc.2024.162144

M3 - Article

VL - 686

JO - Applied Surface Science

JF - Applied Surface Science

SN - 0169-4332

M1 - 162144

ER -