Regensburg 2002 – wissenschaftliches Programm

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HL: Halbleiterphysik

HL 38: Poster 2

HL 38.59: Poster

Donnerstag, 14. März 2002, 16:30–19:00, Poster A

Photodesorption of small molecules adsorbed on ultrathin Ag-films — •Olaf Weiße, Claudia Wesenberg, and Eckart Hasselbrink — Fachbereich Chemie, Universität Essen, D-45117 Essen, Germany

Since the early 1990, Ag is known to grow on the Si(100) surface in the layer-by-layer mode. The resulting surface form an epitaxial Ag(111) layer. These ultrathin Ag-films ( 5-100 ML) are ideal to study the electron dynamics in such films and the influence of the film thickness on charge transfer to the adsorbate and subsequent photodesorption. The growth mode and the surface structure is monitored by using LEED and AES techniques. In our experiments, NO is chosen as the probe molecule. Its adsorption is performed at 90 K on the Ag covered Si (100) surface. Photodesorption is induced using a excimer laser (193 nm) and the desorbed molecules are detected by REMPI and QMS. The film thickness is varied expecting to obtain information about the charge transfer dynamics between the ultrathin Ag-film and the NO adsorbate.