Jan Ingo Flege

  • Citations Per Year
Learn More
Liquid eutectic Pt-Si droplets, migrating across a Si(100) surface due to an applied temperature gradient, interact measurably with surface steps. An analysis of the interaction yields a critical size of hundreds of nanometers below which droplets are constrained to move parallel to monolayer steps. Bunches of closely spaced steps are capable of guiding(More)
Our results indicate that small amounts of an oxide deposited on a stable metal surface can trigger a massive surface reconstruction under reaction conditions. In low-energy electron microscopy (LEEM) experiments, no reconstruction of Cu(111) is observed after chemisorbing oxygen or after reducing O/Cu(111) in a CO atmosphere. On the other hand, LEEM images(More)
Electron scattering by oxygen monolayers on the Ru(0 0 0 1) surface is studied both experimentally and theoretically. Sharp transmission resonances at low energies are revealed and established to originate from critical points of a special kind in the complex band structure of the substrate. Electron reflection from the clean and oxidized Ru(0 0 0 1) is(More)
We present an extensive mesoscale study of the initial gas phase oxidation of Ru(0001), employing in situ low-energy electron microscopy (LEEM), micro low-energy electron diffraction (μ-LEED) and scanning tunneling microscopy (STM). The initial oxidation was investigated in a temperature range of 500-800 K at a constant oxygen pressure of p(O2) = 4 × 10(-5)(More)
CO oxidation over oxygen-rich Ru(0001) surfaces is one of the most studied catalytic oxidation reactions in surface science and of widespread interest as a model system for the redox chemistry of transition metal model catalysts. Here, we present an extensive low-energy electron microscopy (LEEM) and photoemission electron microscopy study of the oxidation(More)
The structural modification of the Ru(0001) surface is followed in real-time using low-energy electron microscopy at elevated temperatures during exposure to molecular oxygen. We observe the nucleation and growth of three different RuO2 facets, which are unambiguously identified by single-domain microspot low-energy electron diffraction (μLEED) analysis(More)
J. I. Flege,1,2,* Th. Schmidt,2 M. Siebert,2 G. Materlik,3 and J. Falta2 1Hamburger Synchrotronstrahlungslabor HASYLAB/DESY, Notkestrasse 85, 22603 Hamburg, Germany 2Institut für Festkörperphysik, Universität Bremen, Otto-Hahn-Allee 1, 28359 Bremen, Germany 3Diamond Light Source Limited, Diamond House, Chilton, Didcot, Oxfordshire OX11 0DE, United Kingdom(More)
Cerium oxide is often applied in today's catalysts due to its remarkable oxygen storage capacity. The changes in stoichiometry during reaction are linked to structural modifications, which in turn affect its catalytic activity. We present a real-time in situ study of the structural transformations of cerium oxide particles on ruthenium(0001) at high(More)
We have studied the oxidation of the Ru(0001) surface by in situ microscopy during exposure to NO2, an efficient source of atomic oxygen, at elevated temperatures. In a previous investigation [Flege et al., Phys. Rev. B: Condens. Matter Mater. Phys., 2008, 78, 165407], at O coverages exceeding 1 monolayer, using the combination of intensity-voltage (I(V))(More)
The pre-adsorption of Ga on Si(112) leads to a drastic change of the morphology of subsequently grown Ge islands. In contrast to the case for Ge growth on bare Si(112), even nanowire growth can be achieved on Ga terminated Si(112). Employing low energy electron microscopy and low energy electron diffraction, the initial phase of Ge nucleation and Ge island(More)