Please use this identifier to cite or link to this item:
Authors: Sheremet, Evgeniya
Milekhin, Alexander G.
Rodriguez, Raul D.
Weiss, Thomas
Nesterov, Maxim
Rodyakina, Ekaterina E.
Gordan, Ovidiu D.
Sveshnikova, Larisa L.
Duda, Tatyana A.
Gridchin, Victor A.
Dzhagan, Volodymyr M.
Hietschold, Michael
Zahn, Dietrich R. T.
Title: Surface- and tip-enhanced resonant Raman scattering from CdSe nanocrystals
Issue Date: 2015 Zeitschriftenartikel 21198-21203 Physical chemistry, chemical physics 17 (2015), S. 21198-21203
ISSN: 1463-9084
Abstract: Surface- and tip-enhanced resonant Raman scattering (resonant SERS and TERS) by optical phonons in a monolayer of CdSe quantum dots (QDs) is demonstrated. The SERS enhancement was achieved by employing plasmonically active substrates consisting of gold arrays with varying nanocluster diameters prepared by electron-beam lithography. The magnitude of the SERS enhancement depends on the localized surface plasmon resonance (LSPR) energy, which is determined by the structural parameters. The LSPR positions as a function of nanocluster diameter were experimentally determined from spectroscopic micro-ellipsometry, and compared to numerical simulations showing good qualitative agreement. The monolayer of CdSe QDs was deposited by the Langmuir–Blodgett-based technique on the SERS substrates. By tuning the excitation energy close to the band gap of the CdSe QDs and to the LSPR energy, resonant SERS by longitudinal optical (LO) phonons of CdSe QDs was realized. A SERS enhancement factor of 2 × 10 3 was achieved. This allowed the detection of higher order LO modes of CdSe QDs, evidencing the high crystalline quality of QDs. The dependence of LO phonon mode intensity on the size of Au nanoclusters reveals a resonant character, suggesting that the electromagnetic mechanism of the SERS enhancement is dominant. Finally, the resonant TERS spectrum from CdSe QDs was obtained using electrochemically etched gold tips providing an enhancement on the order of 10 4 . This is an important step towards the detection of the phonon spectrum from a single QD.
Appears in Collections:08 Fakultät Mathematik und Physik

Files in This Item:
File Description SizeFormat 
C4CP05087H.pdf3,19 MBAdobe PDFView/Open

This item is licensed under a Creative Commons License Creative Commons