Berlin 2008 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 31: Poster II
HL 31.33: Poster
Dienstag, 26. Februar 2008, 16:30–19:00, Poster D
Very small ZnO nanoparticles and their organic ligands studied by Raman spectroscopy and X-ray diffraction — •Maxim Raskin1, Marcel Schumm1, Nicole Pfeiffer2, Julia Harz2, Khellil Bouamama3, Reinhard B. Neder2, and Jean Geurts1 — 1Physikalisches Institut, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany — 2Institut für Mineralogie, Universität Würzburg, Am Hubland, 97074 Würzburg — 3Département de physique, Université Ferhat Abbas, 19000 Sétif, Algeria
ZnO nanoparticles were synthesized with a new wet-chemical method, using 1,3,5-Pentanetrione as ligand molecules. Refinement fits of X-ray powder diffraction diagrams of the particles reveal the expected Wurtzite structure. They also show a nearly spherical particle shape with 2.2 nm diameter, the smallest value for ZnO nanoparticles achieved up to now. The inter-atomic distances match ZnO bulk without relaxation. To study the interface between the ZnO core and the Pentanetrione ligand, we use Raman spectroscopy. The vibration spectra of the ligands bound to the particles differ significantly from the pure ligand ones, i.e. the binding changes the molecule vibration eigenmodes. To interpret these changes in detail, we apply DFT calculations for the structure and the vibration modes of the ligands. The calculations show that (i) the middle oxygen atom in the ligand molecule occupies an exposed position, and (ii) the modes involving this exposed atom are predominantly attenuated by the bonding. This insight into the bonding should allow a systematic selection of further ligand candidates for ultra-small nanoparticle synthesis.