Dresden 2003 – wissenschaftliches Programm
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O: Oberflächenphysik
O 20: Halbleiteroberfl
ächen und -grenzfl
ächen
O 20.7: Vortrag
Dienstag, 25. März 2003, 16:30–16:45, FOE/ANOR
Surface electronic structure of cleaved 6H-SiC surfaces — •Massimo Tallarida1, Ulrich Starke1, Ashwani Kumar1, Karsten Horn1, Olaf Seifarth2 und Lutz Kipp2 — 1Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin — 2Fachbereich Physik der Christian-Albrechts-Universität, Kiel
Cleaved (111) surfaces of silicon and germanium exhibit a metastable (2 x 1) surface reconstruction, which has been interpreted in terms of the π-bonded chain model. It is interesting to compare the structure of these elemental semiconductor surfaces with those of the isoelectronic compound semiconductor silicon carbide, which exhibits a large ionicity in its bonds. However, for the IV-IV compound semiconductor SiC only several stable reconstruc-tions have been studied, prepared by annealing with and without silicon flux or hydrogen treatment. We have investigated the properties of the Si- and C-terminated hexagonal surfaces of 6H-SiC, prepared by cleaving in UHV, using core and valence level photoemission and LEED. A (2 x 2) pattern is observed in LEED, which is interpreted in terms of a 3-domain (2 x 1) surface reconstruction. Valence level spectra are interpreted in terms of bulk and surface-derived bands. We compare our results with theoretical predictions.