title: Surface-enhanced Raman scattering by colloidal CdSe nanocrystal submonolayers fabricated by the Langmuir-Blodgett technique.
abstract: We present the results of an investigation of surface-enhanced Raman scattering (SERS) by optical phonons in colloidal CdSe nanocrystals (NCs) homogeneously deposited on both arrays of Au nanoclusters and Au dimers using the Langmuir-Blodgett technique. The coverage of the deposited NCs was less than one monolayer, as determined by transmission and scanning electron microscopy. SERS by optical phonons in CdSe nanocrystals showed a significant enhancement that depends resonantly on the Au nanocluster and dimer size, and thus on the localized surface plasmon resonance (LSPR) energy. The deposition of CdSe nanocrystals on the Au dimer nanocluster arrays enabled us to study the polarization dependence of SERS. The maximal SERS signal was observed for light polarization parallel to the dimer axis. The polarization ratio of the SERS signal parallel and perpendicular to the dimer axis was 20. The SERS signal intensity was also investigated as a function of the distance between nanoclusters in a dimer. Here the maximal SERS enhancement was observed for the minimal distance studied (about 10 nm), confirming the formation of SERS "hot spots".
authors.affiliation: A.V. Rzhanov Institute of Semiconductor Physics, pr. Lavrentieva 13, Novosibirsk 630090, Russia; Novosibirsk State University, Pirogov str. 2, Novosibirsk 630090, Russia.
authors.forename: Alexander G
authors.initials: AG
authors.lastname: Milekhin
authors.affiliation: A.V. Rzhanov Institute of Semiconductor Physics, pr. Lavrentieva 13, Novosibirsk 630090, Russia.
authors.forename: Larisa L
authors.initials: LL
authors.lastname: Sveshnikova
authors.affiliation: A.V. Rzhanov Institute of Semiconductor Physics, pr. Lavrentieva 13, Novosibirsk 630090, Russia.
authors.forename: Tatyana A
authors.initials: TA
authors.lastname: Duda
authors.affiliation: A.V. Rzhanov Institute of Semiconductor Physics, pr. Lavrentieva 13, Novosibirsk 630090, Russia; Novosibirsk State University, Pirogov str. 2, Novosibirsk 630090, Russia.
authors.forename: Ekaterina E
authors.initials: EE
authors.lastname: Rodyakina
authors.affiliation: Semiconductor Physics, Technische Universität Chemnitz, 09107 Chemnitz, Germany.
authors.forename: Volodymyr M
authors.initials: VM
authors.lastname: Dzhagan
authors.affiliation: Semiconductor Physics, Technische Universität Chemnitz, 09107 Chemnitz, Germany.
authors.forename: Ovidiu D
authors.initials: OD
authors.lastname: Gordan
authors.affiliation: Novosibirsk State University, Pirogov str. 2, Novosibirsk 630090, Russia; International Tomography Center SB RAS, Novosibirsk 630090, Russia.
authors.forename: Sergey L
authors.initials: SL
authors.lastname: Veber
authors.affiliation: Institut für Theoretische Physik, TU Bergakademie Freiberg, 09596 Freiberg, Germany.
authors.forename: Cameliu
authors.initials: C
authors.lastname: Himcinschi
authors.affiliation: A.V. Rzhanov Institute of Semiconductor Physics, pr. Lavrentieva 13, Novosibirsk 630090, Russia; Novosibirsk State University, Pirogov str. 2, Novosibirsk 630090, Russia.
authors.forename: Alexander V
authors.initials: AV
authors.lastname: Latyshev
authors.affiliation: Semiconductor Physics, Technische Universität Chemnitz, 09107 Chemnitz, Germany.
authors.forename: Dietrich R T
authors.initials: DR
authors.lastname: Zahn
keywords: CdSe nanocrystals; dimers; localized surface plasmon resonance; metal nanoclusters; phonons; surface-enhanced Raman spectroscopy