Hamburg 2001 – wissenschaftliches Programm

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O: Oberflächenphysik

O 13: Postersitzung (Adsorption auf Oberfl
ächen, Oberfl
ächenreaktionen, Elektronische Struktur, Epitaxie und Wachstum, Halbleiteroberfl
ächen und Grenzfl
ächen, Oxide und Isolatoren)

O 13.62: Poster

Montag, 26. März 2001, 19:00–22:00, Foyer zu B

STM study of Ge on SiC(0001) — •Kirill Komlev, Bernd Schröter, and Wolfgang Richter — Institut für Festkörperphysik, Friedrich-Schiller-Universität, Max-Wien-Platz 1, D-07743 Jena.

The initial growth of Ge on SiC(0001) reconstructed surfaces has been studied in situ by Scanning Tunneling Microscopy. A monoatomic wetting layer is formed in a Stranski-Krastanov growth mode. The surface structure of this wetting layer depends on the SiC surface preparation. (3 × 3) and (4 × 4) Ge superstructures are observed by growing on the silicon-rich SiC(0001) surface. Surface structures with mainly two-fold periodicity as well as (6 × 6) are observed after Ge deposition on silicon-deficient SiC(0001)-(√3 × √3)-R30^∘ or (6√3 × 6√3) surfaces. Ge nuclei with a density up to 8 × 10¹² cm⁻² and lateral dimensions between 1 and 6 nm depending on the surface treatment are formed on the wetting layer to reduce the strain at higher Ge coverage. Effusion cells with evaporation rates of 0.1 to 1.5 nm/min were used for Ge deposition at substrate temperatures between 470 and 550^∘C. The Si face seems to be a more favourable substrate for a uniform growth of nanocrystals than a C face.