The structure of sodium adsorbed c(2 × 8)Ge(111) surface

• Published in: Surface science Vol. 352; pp. 420 - 424
• Main Authors: Aminpirooz, S., Katsikini, M., Rossner, H., Holub-Krappe, E.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.05.1996
• Subjects: Germanium; Metal-semiconductor interfaces; Single crystal surfaces; Metal-semiconductor interfaces; Germanium; Single crystal surfaces
• ISSN: 0039-6028; 1879-2758
• DOI: 10.1016/0039-6028(95)01173-0

We performed SEXAFS and core level photoemission studies of Na adsorbed on c(2 × 8)-Ge(111) surface at different coverage regimes. The c(2 × 8) LEED pattern of the clean Ge(111) surface changes to a (1 × 1) with higher background after Na adsorption. A plasmon feature appears on the low energy side of Na 2p core level which indicates metallization of the Na overlayer. We determined the NaGe bond length from the SEXAFS data using the theoretical phase shift of NaGe, calculated by FEFF program. SEXAFS model calculations show that Na atoms are adsorbed on threefold-coordinated hollow sites with a NaGe bond length of 2.9 Å and a second nearest neighbour distance of 3.4 Å to the Ge atoms in the second layer.