IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Surface Science Monday Sessions
       Session SS2-MoP

Paper SS2-MoP2
Two-dimensional and Three-dimensional Growth of Ag Islands on a Ge(001) Surface Studied by Photoemission Spectroscopy

Monday, October 29, 2001, 5:30 pm, Room 134/135

Session: Surfaces and Interfaces Poster Session
Presenter: M. Yamada, ISSP, The University of Tokyo, Japan
Authors: M. Yamada, ISSP, The University of Tokyo, Japan
K. Nakatsuji, ISSP, The University of Tokyo, Japan
T. Iimori, ISSP, The University of Tokyo, Japan
S. Ohno, ISSP, The University of Tokyo, Japan
Y. Naitoh, CREST, Japan Science and Technology Corp.
T. Okuda, ISSP, The University of Tokyo, Japan
A. Harasawa, ISSP, The University of Tokyo, Japan
T. Kinoshita, ISSP, The University of Tokyo, Japan
F. Komori, ISSP, The University of Tokyo, Japan
Correspondent: Click to Email
Growth mode of Ag thin films on a Ge(001) surface depends on the substrate temperature: two-dimensional (2D) growth is predominant at low temperatures and three-dimensional (3D) growth becomes dominant at room temperature.@footnote 1@ According to the recipe found by the STM study, we prepared samples composed of 2D (monolayer-thick) or 3D (several-monolayer-thick) Ag islands, and investigated their electronic structure by synchrotron radiation photoemission spectroscopy. A clean Ge(001) surface gives a Ge3d spectrum with a shoulder at the low binding energy side, which is due to surface core-level shift (SCLS) of topmost, 2x1 reconstructed Ge atoms. After Ag deposition at 95K, the shoulder disappeared and the LEED pattern changed to 1x1. These facts indicate that the interaction between Ag and Ge atoms is strong enough to destroy the 2x1 reconstruction in the 2D Ag islands. The Ag4d peak was narrow until Ag thickness of 1.3Å, indicating that the Ag-Ag interaction is weak in the 2D Ag islands. Above 1.3Å a new broad component was observed in the Ag4d spectrum, which suggested the presence of 3D Ag islands. The breadth of the new component indicates the strong Ag-Ag interaction in the 3D Ag islands. When Ag was deposited on a Ge(001) surface at room temperature, the LEED pattern remained to be 2x1 and the shoulder due to the SCLS did not disappear in the Ge3d spectrum. The Ag4d band was broad and bulk-like. These facts indicate that Ag grows three-dimensionally and leaves intact most of the clean Ge(001)-(2x1) surface at room temperature. @FootnoteText@ @footnote 1@ F. Komori et al., Surf. Sci., 438 (1999) 123.