Regensburg 2010 – scientific programme
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MM: Fachverband Metall- und Materialphysik
MM 26: Poster Session
MM 26.39: Poster
Tuesday, March 23, 2010, 14:45–16:30, Poster C
Low Energy Excitations in Semiconductor Nanoparticles — •Andreas Hartmann1, Darius Pohl1, Ludwig Schultz1, Stephen Hickey2, Alexander Eychmüller2, and Bernd Rellinghaus1 — 1IFW Dresden, Helmholtzstr. 20, D-01069 Dresden, Germany — 2TU Dresden, Physical Chemistry and Electrochemistry, Bergstr. 66b, D-01062 Dresden, Germany
Low energy excitations such as plasmons or excitons and also the semiconductor band gap usually depend strongly on the dimensionality and the size of the material. As a consequence, the control of various electronic properties of semiconductor nanoparticles by merely controlling their size is since long a vital research field. The vast majority of the investigations is, however, focussed on characterising the properties of particle ensembles, and only little work is so far dedicated to the correlation of size, structure, and electronic properties in individual isolated particles. Modern aberration-corrected HRTEM in combination with local EELS provides an effective tool to investigate such correlations. The potential of using HRTEM with a monochromated electron source at low acceleration voltages offers new opertunities to characterize low energy excitations with high energy and spatial resolutions. Here, the effective suppression of Cerenkov radiation backgrounds upon reducing the acceleration voltage and the gain in energy resolution by using a monochromated beam is largely beneficial to low energy EELS. The potential and the limitations of this method are explored for the example of colloidal wide band gap Zn-O nanoparticles.