Berlin 2012 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 35: Poster Session II (Polymeric biomolecular films; Nanostructures; Electronic structure; Spin-orbit interaction; Phase transitions; Surface chemical reactions; Heterogeneous catalysis; Particles and clusters; Surface magnetism; Electron and spin dynamics; Surface dynamics; Methods; Electronic structure theory; Functional molecules)
O 35.88: Poster
Dienstag, 27. März 2012, 18:15–21:45, Poster B
Surface and bulk states at Ge(100) - Binding energies, lifetimes and dispersions — •Jens Kopprasch1,2, Kristof Zielke1,2, Cornelius Gahl1,2, Christian Eickhoff1,2, Jörg Schäfer3, and Martin Weinelt1,2 — 1Max-Born-Institut, Max-Born-Straße 2a, 12489 Berlin, Germany — 2Freie Universität Berlin, Fachbereich Physik, Arnimallee 14, 14195 Berlin, Germany — 3Universitat Würzburg, Fakultät für Physik und Astronomie, Am Hubland, 97074 Würzburg, Germany
Germanium (Ge) is a material of growing interest in semiconductor industry. Increased industrial engineering has opened a broad field of applications for Ge, e.g. solar cells, high-power transistors, infrared optics and X-ray detectors.
We observed band bending at n-doped samples and flat-band conditions on p-doped samples. In this way we determine the Ge(100) ionisation potential. A series of two-photon-photoemission measurements with variing photon energies allows us to identify the dangling-bond states Dup, Ddown and the first image-potential state n=1. We determined the binding energies, lifetimes and dispersions of these states. Furthermore we observed bulk-band transitions at 90K which lead to carrier dynamics on a picosecond timescale. In addition we observe ultrafast interband scattering between the conduction band and Γ- valley.