Düsseldorf 2007 – wissenschaftliches Programm
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A: Fachverband Atomphysik
A 22: Poster II - Atomic clusters
A 22.3: Poster
Donnerstag, 22. März 2007, 16:30–18:30, Poster B
Size-selected cluster deposition as studied by STM — •Chunrong Yin1, Bernd von Issendorff1, Stefanie Duffe2, Thomas Irawan2, Markus Bieletzki2, Torsten Richter2, Benedikt Sieben2, and Heinz Hövel2 — 1Universität Freiburg, FMF, 79104 Freiburg, Germany — 2Universität Dortmund, Experimentelle Physik I, 44221 Dortmund, Germany
It is very interesting to compare the electronic structure of identical clusters in the free beam and supported on surfaces.
For free clusters the quantized electronic structure as well as the charging in the photoemission process can be studied with photoemission. For clusters at surfaces a topographic investigation with STM was combined with STS and UPS for the study of the electronic structure. Here we will present results for the deposition of mass selected Ag clusters using a cluster machine consisting of a magnetron sputter gas aggregation source, a differential pumping stage with a cryopump and a high transmission infinite range mass selector ( m/Δ m≥ 50). The cluster source is combined with a surface-science facility containing a low-temperature STM and high-resolution UPS. With cluster currents of e.g. up to 93 pA for Ag55+, the deposition time for a reasonable cluster coverage was of the order of 10 minutes. Extremely narrow height distributions (h/Δ h≈ 20) were observed with STM for mass-selected clusters in the size range of Ag55+ to Ag923+ deposited with low kinetic energy.