Berlin 2008 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 51: Poster IV
HL 51.61: Poster
Donnerstag, 28. Februar 2008, 16:30–19:00, Poster D
Characterization of MgxZn1−xO-layers grown by plasma assisted molecular beam epitaxy — •Bernhard Laumer, Thomas A. Wassner, Stefan Maier, Jochen Bruckbauer, Martin Stutzmann, and Martin Eickhoff — Walter Schottky Institut, Technische Universität München, Am Coulombwall 3, 85748 Garching, Germany
In order to reduce the large lattice mismatch, an optimized MgO-ZnO double buffer structure was employed to grow MgxZn1−xO layers on (0001)-sapphire by plasma assisted molecular beam epitaxy. The Mg concentration x was varied between 0 and 0.3. Structural analysis was carried out by high resolution X-ray diffraction (HRXRD) to extract the lattice parameters as well as the density of edge- and screw-type dislocations as a function of the Mg-content. The c-lattice parameter was found to decrease with increasing Mg content, whereas the a-lattice parameter remained constant. The influence of Mg-incorporation on the optical properties was investigated by temperature-dependent photoluminescence and absorption spectroscopy. With increasing Mg content effects due to disorder introduced by the Mg incorporation like a pronounced Stokes-shift and alloy broadening were observed. The background charge carrier concentration as determined by Hall measurements decreased with increasing Mg incorporation from 5 · 1018 to 7 · 1017 cm−3.