Berlin 2015 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 99: Semiconductor Substrates: Structure, Epitaxy and Growth
O 99.2: Vortrag
Freitag, 20. März 2015, 10:45–11:00, MA 042
Atomic structure of terbium-induced nanostructures on Si(111) — •Martin Franz, Jan Große, Robert Kohlhaas, and Mario Dähne — Technische Universität Berlin, Institut für Festkörperphysik, Berlin
Rare earth metals are known to form a variety of very interesting self-assembled nanostructures on silicon surfaces. Examples are the metallic nanowires that form on the Si(001) and the Si(557) surface. On the planar Si(111) surface, the formation of two- and three-dimensional layers is observed.
Here, we report on a detailed scanning tunneling microscopy study on the growth and the atomic structure of terbium-induced nanostructures growing on the Si(111)7×7 surface for different terbium coverage. At extremely low coverage, the 7×7 substrate acts as a template for the growth of terbium-induced magic clusters. In the submonolayer regime, a 2√3×2√3 superstructure, a chain-like 5×2 superstructure, and elongated islands with a 2×1 reconstruction on top are found. The 5×2 phase consists of alternating silicon Seiwatz and honeycomb chains with terbium rows in between. The observed different configurations can be explained by registry shifts between neighboring terbium rows or defects within one row. At higher coverage, the two-dimensional TbSi2 monolayer forming a 1×1 reconstruction and the three-dimensional Tb3Si5 multilayer forming a √3×√3 reconstruction are found.
This work was supported by the DFG through FOR 1282 project D.