Berlin 2018 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 89: Oxide and Insulator Surfaces: Structure, Epitaxy and Growth I

O 89.10: Vortrag

Donnerstag, 15. März 2018, 12:45–13:00, MA 041

A mesoscopic view on ultra-thin germania films on Ru(0001) — •Alexander Fuhrich¹, Thomas Schmidt¹, Dietrich Menzel^1,2, and Hans-Joachim Freund¹ — ¹Department of Chemical Physics, Fritz-Haber-Institute of the Max-Planck-Society, Berlin, Germany — ²Physik-Department E20, Technische Universität München, Garching, Germany

The silica bi-layer system on Ru(0001) has been intensely studied by different techniques [1,2]. However, the modification of these ultrathin films by using germanium instead of silicon offers many interesting opportunities for catalysis and the understanding of the growth of ultra-thin semiconductor oxides on metal single crystals. Using spectro-microscopy (LEEM, LEED, XPEEM and XPS), we studied the growth and structures of ultra-thin germania supported on Ru(0001). The growth of germanium and germania on Ru(0001) was observed in real-time and in-situ at mesoscopic scale. The morphology and structure of the Germania films will be discussed in dependence on preparation parameters . The presence of oxygen reduces the diffusion of germanium on Ru(0001). Though deposited in UHV, germanium is partially oxidized by oxygen pre-covered on the Ru surface. The fully oxidized Germania film exhibits a 2x2 structure on Ru(0001) and, up to now, no evidence was found for a vitreous germania phase on Ru(0001) like it is the case for silica.

References 1. H.W. Klemm, G. Peschel, E. Madej, A. Fuhrich, M. Timm, D. Menzel, Th. Schmidt, H.-J. Freund, Surf. Sci. 646, 45-51 (2016) 2. S. Shaikhutdinov, H.-J. Freund, Adv. Mater 25, 49-67 (2013)