Regensburg 2010 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 24: Particles and clusters

O 24.2: Vortrag

Dienstag, 23. März 2010, 10:45–11:00, H34

RHEED Study of Au-induced Surface Reconstructions and 3D AuSi Nanoparticles — •Stephan Bartling, Ingo Barke, Kristian Sell, Stefan Polei, Viola von Oeynhausen, and Karl-Heinz Meiwes-Broer — Institut für Physik, Universität Rostock, 18051 Rostock, Germany

The contribution focuses on in situ reflection high energy electron diffraction (RHEED) of Au/Si(111). Three different surface reconstructions can be observed in recorded RHEED patterns during Au evaporation in the sub-monolayer regime. Recently, the ideal Au coverage for the Si(111)5 × 2-Au reconstruction has been revised [1]. The result of Θ=0.6ML is confirmed by the coverage-dependent intensity of spots.

After Au deposition of >1ML on vicinal Si(111) three-dimensional gold-rich AuSi nanoparticles are formed via Stranski-Krastanov growth. A mean particle height of 5.8nm has been determined from large-scale STM images for ≈ 3ML Au. The RHEED diffraction pattern can be modeled by a quasi close-packed structure with rhombohedral unit cell. We do not observe flat top facets reported for similar preparation conditions [2]. This is in agreement with the crystal orientation determined by RHEED.
[1] I. Barke et al., Phys. Rev. B 79, 155301 (2009)
[2] E. Moyen et al., Appl. Phys. Lett. 94, 233101 (2009)