Berlin 2005 – wissenschaftliches Programm
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O: Oberflächenphysik
O 25: Zeitaufgelöste Spektroskopie II
O 25.4: Vortrag
Samstag, 5. März 2005, 15:45–16:00, TU EB420
Electron dynamics in thin Ag-films on Si(100) — •Claudia Kennerknecht1, Sven Schramm1, Walter Pfeiffer1, Olaf Weiße2, and Eckart Hasselbrink2 — 1Physikalisches Institut, Universität Würzburg, Am Hubland, 97070 Würzburg — 2Fachbereich Chemie, Universität Duisburg-Essen, Universitätstr. 5, 45117 Essen, Germany
The properties of Ag-films of few nanometers thickness differ substantially from bulk materials. So called quantum well states appear because of the confinement in one dimension [1]. In addition, thin films show unexpected catalytic bevior. Using time-resolved multiphoton photoemission spectroscopy we gain information about the transient electron distribution of our sample. The spectra reveal the internal thermalization and cooling of the electron gas.
Measurements on thin Ag-films on n-doped Si(100) show a wavelength dependence which can be explained by different absorption in the Ag-film and the Si substrate. Time-resolved measurements reveal larger relaxation times compared to measurements on thin Ag-films on MgO(100) and single crystals [2]. We attribute this influence of the substrate to carrier injection from the photoexcited Si.
[1] Matsuda et al, Phys. Rev. B 65 (2002)
[2] Aeschlimann et al, Appl. Phys. A 71 (2000)