Regensburg 2013 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 91: Poster Session: Quantum dots and wires: preparation & characterization & optical properties & transport properties

HL 91.10: Poster

Donnerstag, 14. März 2013, 16:00–20:00, Poster A

Raman characterization of electrically biased polymer quantum dot composites — •Prahlad M Mohandas¹, Daniel Lehmann¹, Ovidiu D Gordan¹, Istvan S Todor², Christian Spudat³, Jörg Martin³, Michael Thomas Müller⁴, Thomas Geßner³, and Dietrich R. T. Zahn¹ — ¹Semiconductor Physics, Chemnitz University of Technology, D-09107 Chemnitz, Germany — ²Department of Solid State Physics, Faculty of Physics, Babes-Bolyai University, Cluj-Napoca, Romania — ³Fraunhofer-Institut für Elektronische Nanosysteme, Technologie-Campus 3, D-09126 Chemnitz, Germany — ⁴Leibniz-Institut für Polymerforschung Dresden e.V., Polymerreaktionen und Blends, Hohe Straße 6, D-01069 Dresden, Germany

Thin films of a polymer/quantum dot composite are characterized using Raman and photoluminescence spectroscopy under electrically biased conditions in order to investigate the effect of voltage on the quantum dot charging behaviour. The quantum dots are CdSe/ZnS core/shell quantum dots, mixed homogeneously in polymethylmethacrylate (PMMA) polymer. The PMMA-CdSe/ZnS composite film was deposited on a glass substrate using spin-coating technique. The polymer quantum dot composites were biased between +48V and -48V. Peaks corresponding to CdSe longitudinal optical (LO) phonon and ZnS LO phonon were observed at 206 cm-1 and 272 cm-1, respectively. Quenching of phonon bands due to charging of quantum dots by the applied voltage is observed. The effect of quenching depends and varies based on the sign of the applied voltage.