Regensburg 2007 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 13: Poster 1
HL 13.44: Poster
Montag, 26. März 2007, 15:00–17:30, Poster A
Preparation of silicon nanoparticle films for single particle spectroscopy — •Matthias Offer1, Cedrik Meier1, Stephan Lüttjohann1, Andreas Gondorf1, Axel Lorke1, and Hartmut Wiggers2 — 1Experimental Physics and CeNIDE, University of Duisburg-Essen, Lotharstrasse 1, D-47048 Duisburg, Germany — 2Institute of Combustion and Gas Dynamics, University of Duisburg-Essen, Lotharstrasse 1, D-47048 Duisburg, Germany
A major obstacle for spectroscopy of single nanoparticles, obtained by chemical synthesis is the difficulty to deposit dilute layers of isolated nanoparticles on a suitable substrate. In the case of silicon nanoparticles, which are synthesized from the gas-phase without, e.g., organic surface functionalization or modification, there is also a strong tendency towards agglomeration. By dispersing the nanoparticles in different solutions, we have been able to deposit films of isolated particles. We use different organic and aqueous solvents. In the latter case, we find that by varying the pH value we can modify the zeta-potential and reach a stabilized solution. After deposition, we find ring-like structures with a particle-size gradient that leads to a position-dependent energy shift in the PL signal. This can be explained in the framework of the DLVO theory. We compare the deposition results for silicon nanoparticles to results obtained using commercially available PbS nanoparticles with functionalized surfaces.