Regensburg 2013 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 15: Focus Session: Crystalline n-type semiconducting oxides - SnO2, Ga2O3, and In2O3 for novel devices (HL, jointly with O)
HL 15.4: Talk
Monday, March 11, 2013, 16:30–16:45, H2
Surface structure of metal oxides via Fast Atom Diffraction — •Marco Busch1, Eric Meyer1, Jan Seifert1, Helmut Winter1, Klaus Irmscher2, Zbigniew Galazka2, and Roberto Fornari2 — 1Humboldt-Universität zu Berlin, Institut für Physik, Newtonstrasse 15, D-12489 Berlin, Germany — 2Leibniz-Institut für Kristallzüchtung, Max-Born-Strasse 2, D-12489 Berlin, Germany
Fast light atoms (H and 4He) and molecules (H2) with energies from 200 eV up to several keV are grazingly scattered from clean and flat surfaces. For scattering along low-indexed axial channels, we observe defined diffraction patterns in the angular distributions of scattered projectiles, which can be ascribed to Fast Atom Diffraction (FAD) with de Broglie wavelengths as low as about 10−3 Å. As example, we have investigated the quantum scattering from the cleaved (100) surface of a Ga2O3 single crystal, grown by the Czochralski method following by in situ annealing. The splittings of Bragg peaks and their intensity modulations were so far exploited to deduce information on the arrangement of atoms in the topmost surface layer. Furthermore, diffraction effects were present in the regime of surface channeling, where quantum scattering is considered for the motion parallel to the surface. For the Al2O3(1120) surface we found, that beside the normal coherence also the longitudinal coherence is preserved, so that Laue circles are observed. Then, quantum scattering from surfaces gives rise to interesting features and enhances the resolution of FAD by one order of magnitude. As example, we have resolved the (12x4) superstructure on the Al2O3(1120) surface obtained after annealing to about 2000 K.