title: Linear and nonlinear optical properties of functionalized CdSe quantum dots prepared by plasma sputtering and wet chemistry.
abstract: We develop an innovative manufacturing process, based on radio-frequency magnetron sputtering (RFMS), to prepare neat CdSe quantum dots (QDs) on glass and silicon substrates and further chemically functionalize them. In order to validate the fabrication protocol, their optical properties are compared with those of QDs obtained from commercial solutions and deposited by wet chemistry on the substrates. Firstly, AFM measurements attest that nano-objects with a mean diameter around 13 nm are located on the substrate after RFMS treatment. Secondly, the UV-Vis absorption study of this deposited layer shows a specific optical absorption band, located at 550 nm, which is related to a discrete energy level of QDs. Thirdly, by using two-color sum-frequency generation (2C-SFG) nonlinear optical spectroscopy, we show experimentally the functionalization efficiency of the RFMS CdSe QDs layer with thiol derived molecules, which is not possible on the QDs layer prepared by wet chemistry due to the surfactant molecules from the native solution. Finally, 2C-SFG spectroscopy, performed at different visible wavelengths, highlights modifications of the vibration mode shape whatever the QDs deposition method, which is correlated to the discrete energy level of the QDs.
authors.affiliation: Univ Paris-Sud, Laboratoire de Chimie-Physique, CNRS, Bâtiment 201P2, 91405 Orsay, France.
authors.forename: Christophe
authors.initials: C
authors.lastname: Humbert
authors.affiliation: GRASP - Biophotonics, University of Liege, Institute of Physics, Allée du 6 août 17, 4000 Liège, Belgium.
authors.forename: Abdellatif
authors.initials: A
authors.lastname: Dahi
authors.affiliation: Univ Paris-Sud, Laboratoire de Chimie-Physique, CNRS, Bâtiment 201P2, 91405 Orsay, France.
authors.forename: Laetitia
authors.initials: L
authors.lastname: Dalstein
authors.affiliation: Univ Paris-Sud, Laboratoire de Chimie-Physique, CNRS, Bâtiment 201P2, 91405 Orsay, France.
authors.forename: Bertrand
authors.initials: B
authors.lastname: Busson
authors.affiliation: GRASP - Biophotonics, University of Liege, Institute of Physics, Allée du 6 août 17, 4000 Liège, Belgium.
authors.forename: Marjorie
authors.initials: M
authors.lastname: Lismont
authors.affiliation: GREEnMat - LCIS, University of Liege, Institute of Chemistry, Allée de la Chimie 3, 4000 Liège, Belgium.
authors.forename: Pierre
authors.initials: P
authors.lastname: Colson
authors.affiliation: GRASP - Biophotonics, University of Liege, Institute of Physics, Allée du 6 août 17, 4000 Liège, Belgium. Electronic address: Laurent.Dreesen@ulg.ac.be.
authors.forename: Laurent
authors.initials: L
authors.lastname: Dreesen
mesh_terms: D019187:Cadmium Compounds / Q000737:chemistry*; D008027:Light; D036103:Nanotechnology; D045663:Quantum Dots / Q000737:chemistry* / Q000648:ultrastructure; D018036:Selenium Compounds / Q000737:chemistry*; D012825:Silicon / Q000737:chemistry; D013056:Spectrophotometry, Ultraviolet; D013499:Surface Properties
chemical_list: D019187:Cadmium Compounds; D018036:Selenium Compounds; C058667:cadmium selenide; D012825:Silicon
keywords: Magnetron sputtering; Optical properties; Quantum dots; Sum-frequency generation