Resonant Tip-enhanced Raman Scattering by CdSe Nanocrystals on Plasmonic Substratesстатья
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Дата последнего поиска статьи во внешних источниках: 9 декабря 2020 г.
Аннотация:Tip-enhanced Raman scattering (TERS) has recently emerged as a powerful technique forstudying local properties of low dimensional materials. Being a plasmon driven system, adramatic enhancement of the TERS sensitivity can be achieved by the proper choice of aplasmonic substrate in the so-called gap-mode configuration. Here, we investigate the phononproperties of CdSe nanocrystals (NCs) utilizing gap-mode TERS. Using the Langmuir-Blodgetttechnique, we deposited homogeneously submonolayers of colloidal CdSe NCs on two different nanostructured plasmonic substrates. Amplified by resonant gap-mode TERS, the scattering by optical phonon modes of CdSe NCs is markedly enhanced making it possible to observe up to the third overtone of the LO mode reliably. The home-made plasmonic substrates and TERS tips allowthe analysis of the TERS images of CdSe phonon modes with nanometer spatial resolution. TheCdSe phonon scattering intensity is strongly correlated with the local electromagnetic fielddistribution across the plasmonic substrates.