Dresden 2014 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

SYOM: Symposium One-dimensional Metals: Reality or Fiction

SYOM 2: Posters: One-Dimensional Metals: Reality or Fiction (jointly organized by DS, HL, O, TT)

SYOM 2.16: Poster

Donnerstag, 3. April 2014, 16:00–19:00, P1

Optical and electronic properties of rare-earth silicide nanowires on vicinal Si(001) — •Sandhya Chandola¹, Eugen Speiser¹, Stephan Appelfeller², Martin Franz², Norbert Esser¹, and Mario Dähne² — ¹Leibniz-Institut für Analytische Wissenschaften - ISAS - e.V., Berlin — ²Institut für Festkörperphysik, TU Berlin

Dy and Tb silicide nanowire structures on vicinal Si(001) surfaces are studied using in-situ Reflectance Anisotropy Spectroscopy (RAS) and Scanning Tunneling Microscopy (STM). Two different types of structures, metallic nanowires or a wire-like reconstruction, are formed by molecular beam epitaxy depending on the coverage and the annealing temperature. RAS of clean surfaces shows the typical features due to dangling bonds at the steps and Si dimers on the terraces. The silicide growth has a significant effect on the optical anisotropy, e.g. a feature develops at 3.8 eV for both structure types. This peak disappears after the surface is contaminated, confirming that it is unambiguously related to surface state transitions. Furthermore, RAS can identify how well-ordered the metallic nanowires are by the relative magnitude of this peak. The feature of the dangling bonds at the steps is significantly more affected for the wire-like reconstruction than for the metallic nanowires, as supported by the STM data showing that the reconstruction decorates many steps, thereby saturating the dangling bonds. Thus, RAS can be used as an optical fingerprint to distinguish different silicide nanowire structures. This work was supported by the DFG through FOR 1700 projects E2 and E3.