Dresden 2006 – wissenschaftliches Programm
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O: Oberflächenphysik
O 34: Particles and clusters II
O 34.6: Vortrag
Donnerstag, 30. März 2006, 12:30–12:45, WIL A317
Characterisation of silver nanoparticles on magnesium oxide — •M. Alschinger1, Y. Chen2, M. Di Vece2, F. Hubenthal1, R.E. Palmer2, and F. Träger1 — 1Institut für Physik, Universität Kassel, Kassel — 2Nanoscale Physics Research Laboratory, The University of Birmingham, Birmingham, UK
Determination of the dimensions of supported nanoparticles has long been a very important issue that can most reliably be accomplished by transmission electron microscopy (TEM). Such measurements are, however, time consuming and require laborious preparation of the samples. In order to develop a more straightforward, easy to apply and accurate alternative, optical spectroscopy and its potential for the determination of the particle size and shape has been examined in detail here. The results were complete by AFM images and compared to data derived from TEM pictures. First, Ag nanoparticles have been prepared in vacuum by deposition and nucleation of silver atoms on magnesium oxide substrates. Subsequently, the optical spectra were recorded and compared to theoretical spectra based on the quasistatic approximation in order to establish a relation between the size and shape of the particles. AFM has been used to measure the size and the size distribution of the particles. In a second step the same kind of particles was prepared for TEM experiments from which we could obtain precise data for comparison. The most important result is that modelling of the optical spectra revealed a relation between the size and shape of the particles that is in accord with the TEM results and therefore forms a basis for reliable determination of the dimensions of nanoparticles by measuring their optical spectra.