Dresden 2006 – scientific programme

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CPP: Chemische Physik und Polymerphysik

CPP 12: POSTER Colloids, Nanoparticles and Self-Organizing Systems

CPP 12.5: Poster

Tuesday, March 28, 2006, 17:00–19:00, P3

Vibrational properties of ZnO and Zn_1−xMn_xO nanoparticles and ligand-nanoparticle interactions studied by Raman spectroscopy — •M. Schumm¹, M. Lentze¹, C. Barglik-Chory², and J. Geurts¹ — ¹Physikalisches Institut der Universität Würzburg, Am Hubland, 97074 Würzburg — ²Lehrstuhl für Silicatchemie, Universität Würzburg, Röntgenring 11, 97070 Würzburg

Nanostructured systems of the large bandgap semiconductor ZnO have attracted a great deal of attention in the recent past due to its special optical properties and various potential applications. Theoretical predictions of ferromagnetic behaviour at room temperature focused the interest among the group of diluted magnetic semiconductors on (Zn,Mn)O nanostructures.

We report on a study of wet chemically synthesised ZnO and (Zn,Mn)O nanoparticles (diameters 3-12 nm) by VIS micro- and Fourier Transform NIR Raman spectroscopy. Special attention was paid to properties of the binding between the ligands and the nanoparticle surface and to interactions between molecular vibrations of the ligands and the phonons of the nanocrystallites. Besides the verification of ligand binding to the particles’ surface, ligand-induced strengthening of nanoparticle phonon modes and the formation of coupled modes between nanoparticle phonons and ligand vibrations were observed. Furthermore, the Raman spectra show confinement induced phonon peak shifting and broadening compared to the corresponding bulk material. Finally, for the Zn_1−xMn_xO nanoparticles the successful substitutional incorporation of Mn in the Zn sublattice was proven by its specific vibration modes in the Raman spectrum.