Berlin 2014 – wissenschaftliches Programm

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P: Fachverband Plasmaphysik

P 17: Poster Session - Helmholtz Graduate School for Plasma Physics

P 17.18: Poster

Mittwoch, 19. März 2014, 16:30–18:30, SPA Foyer

Time-resolved measurements of cluster mass distribution in a pulsed gas aggregation system — •Steffen Drache, Florian Berg, Vitezslav Straňák, Marina Ganeva, Harm Wulff, and Rainer Hippler — Institut für Physik, Ernst-Moritz-Arndt Universität, Felix-Hausdorff-Straße 6, D-17487 Greifswald

Owing to their large surface to volume ratio, nano-size particles (clusters) exhibit unique physical and chemical properties. These particles of a few nm size can find application in, e.g. micro electronics, chemical catalysts, or quantum dots. In our experiment Cu cluster particles were synthezised in a gas aggregation nanocluster source. In contrast to the conventional constant gas flow the buffer gas was delivered in pulses. The aim was to alter the clusters mass distribution by means of a time dependent pressure in the aggregation region. For time-resolved analysis a labview-controlled quadrupole mass filter (QMF) was installed and the pressure in the cluster source was also monitored. As a first result, cluster current and mass quickly respond to pressure changes. Since the QMF mass range is limited, deposited clusters were also examined by atomic force microscopy (AFM). Results show a broadened mass distribution compared to the unpulsed experiment. Finally, clusters were co-deposited during reactive Ti magnetron sputtering in an Ar/O₂ atmosphere to study nanoparticles embedded in a TiO₂ matrix. GIXD and XPS reveal that clusters become x-ray amorphous and oxidized in the confining TiO₂ matrix.