Dresden 2009 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
O: Fachverband Oberflächenphysik
O 27: Poster Session I (Methods: Scanning probe techniques; Methods: Atomic and electronic structure; Methods: Molecular simulations and statistical mechanics; Oxides and Insulators: Clean surfaces; Oxides and Insulators: Adsorption; Oxides and Insulators: Epitaxy and growth; Semiconductor substrates: Clean surfaces; Semiconductor substrates: Epitaxy and growth; Semiconductor substrates: Adsorption; Nano- optics of metallic and semiconducting nanostructures; Electronic structure; Methods: Electronic structure theory; Methods: other (experimental); Methods: other (theory); Solutions on surfaces; Epitaxial Graphene; Surface oder interface magnetism; Phase transitions; Time-resolved spectroscopies)
O 27.51: Poster
Dienstag, 24. März 2009, 18:30–21:00, P2
Decomposition of the Si(111)-2×1 Surface Reconstruction at Room Temperature: an STM Study — •Thomas K. A. Spaeth1, Martin Wenderoth1, Karolin Löser1, Jens K. Garleff2, and Rainer G. Ulbrich1 — 1IV. Phys. Inst., Georg August Univ. Göttingen, Germany — 2PSN, Eindhoven University of Technologie, the Nederlands
The π-bonded chains of the Si(111)-2×1 reconstructed surface are highly anisotropic with quasi 1-d electronic properties [1, 2]. We prepared the surfaces by cleaving bulk crystals. During STM measurements in UHV (8·10−10mbar to 6·10−11mbar) we observed a gradual decomposition of the Si(111)-2×1 surface structure. It starts with small holes which grow gradually. The new surface shows no reconstruction or any periodic structure. Comparing the topographic height with monatomic step as a reference we find that the step height between the original reconstruction and the new surface is only half the height difference of the monolayer. By measurements at diverse UHV pressures we find a variation of the rate of decomposition: with increasing pressure the decomposition takes several days at 6·10−11mbar, and only a few hours at 8·10−10mbar. Finally the surface ordering vanishes completely. For this type of surface no further degradation is observed. Our findings indicate that the partial and finally even complete removal of the first atomic layer leads to a more stable surface structure which is not long-range ordered.
[1] M. Rolfing and S. G. Louie, PRL 83 (4), 856 (1999)
[2] J. K. Garleff et al., PRB 76, 125322 (2007)