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O: Oberflächenphysik
O 25: Epitaxie und Wachstum II
O 25.5: Vortrag
Dienstag, 9. März 2004, 16:45–17:00, H39
Epitaxial growth of Ag on W(110) studied by Reflectance Difference Spectroscopy — •L. D. Sun1, M. Hohage1, P. Zeppenfeld1, C. Deisl2, and E. Bertel2 — 1Institute of Experimental Physics, Johannes-Kepler University Linz — 2Institute of Physical Chemistry, University of Innsbruck
The epitaxial growth of Ag on W(110) at room temperature has been studied by Reflectance Difference Spectroscopy (RDS). The first two Ag layers follow a layer-by-layer growth and show a distorted Ag(111) structure. The anisotropic electronic transitions in the Ag film contribute substantially to the optical anisotropy and can thus be used to monitor the growth process. The evolution of the RDS spectrum strongly depends on the Ag coverage. In particular, the RDS intensity at 4.7 eV increases monotonically during the formation of the first Ag layer, whereas the signal at 4.2 eV responds to the growth of the second layer. When the thickness of the Ag film exceeds 3 monolayers, the RDS spectrum shows a derivative like feature around a photon energy of 4 eV which can be attributed to the onset of the bulk d-band transition of Ag. This observation suggests the formation of a Ag bulk band structure at this growth stage and thus is consistent with the growth of 3D islands on top of the bilayer. These results are in good agreement with previous studies on the crystallographic [1, 2] and electronic structure [3] of the Ag/W(110) system. [1] E. Bauer et al., J. Appl. Phys. 48 (1977) 3773 [2] Y. Yang et al., Surf. Sci. 276 (1992) 341. [3] A. Elbe et al., Surf. Sci. 397 (1998) 346