title: Analysis of temporal evolution of quantum dot surface chemistry by surface-enhanced Raman scattering.
abstract: Temporal evolution of surface chemistry during oxidation of silicon quantum dot (Si-QD) surfaces were probed using surface-enhanced Raman scattering (SERS). A monolayer of hydrogen and chlorine terminated plasma-synthesized Si-QDs were spin-coated on silver oxide thin films. A clearly enhanced signal of surface modes, including Si-Clx and Si-Hx modes were observed from as-synthesized Si-QDs as a result of the plasmonic enhancement of the Raman signal at Si-QD/silver oxide interface. Upon oxidation, a gradual decrease of Si-Clx and Si-Hx modes, and an emergence of Si-Ox and Si-O-Hx modes have been observed. In addition, first, second and third transverse optical modes of Si-QDs were also observed in the SERS spectra, revealing information on the crystalline morphology of Si-QDs. An absence of any of the abovementioned spectral features, but only the first transverse optical mode of Si-QDs from thick Si-QD films validated that the spectral features observed from Si-QDs on silver oxide thin films are originated from the SERS effect. These results indicate that real-time SERS is a powerful diagnostic tool and a novel approach to probe the dynamic surface/interface chemistry of quantum dots, especially when they involve in oxidative, catalytic, and electrochemical surface/interface reactions.
authors.affiliation: Dutch Institute for Fundamental Energy Research (DIFFER), P. O. Box 6336, 5600 HH Eindhoven, The Netherlands.|Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands.
authors.forename: İlker
authors.initials: İ
authors.lastname: Doğan
authors.affiliation: Department of Mechanical Sciences and Engineering, Tokyo Institute of Technology, 2-12-1, O-Okayama, Meguro, 1528550 Tokyo, Japan.
authors.forename: Ryan
authors.initials: R
authors.lastname: Gresback
authors.affiliation: Department of Mechanical Sciences and Engineering, Tokyo Institute of Technology, 2-12-1, O-Okayama, Meguro, 1528550 Tokyo, Japan.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Nozaki
authors.affiliation: Dutch Institute for Fundamental Energy Research (DIFFER), P. O. Box 6336, 5600 HH Eindhoven, The Netherlands.|Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands.
authors.forename: Mauritius C M
authors.initials: MC
authors.lastname: van de Sanden