Dresden 2009 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 40: ZnO: preparation and characterization III
HL 40.2: Vortrag
Donnerstag, 26. März 2009, 09:45–10:00, BEY 118
Investigations of ZnO/Zn1−xCdxO double heterostructures grown by pulsed laser deposition — •Martin Lange, Jan Zippel, Gabriele Benndorf, Christian Czekalla, Holger Hochmuth, Michael Lorenz, and Marius Grundmann — Universität Leipzig, Institut für Experimentelle Physik II, Linnéstr. 5, D-04103 Leipzig, Germany
ZnO/Zn1−xCdxO double heterostructures have been grown on a-plane sapphire substrates by pulsed laser deposition. The oxygen partial pressure and the substrate temperature was varied to fabricate samples with high cadmium content and hence smaller bandgap energy than ZnO but though high luminescence yield.
The samples have been studied with temperature dependent photoluminescence in the temperature range from 2 to 295 K. A S-shape behaviour for the peak energy of the Zn1−xCdxO-luminescence was observed and the standard derivation of the potential σ was estimated with a fit of this S-shape. A large number of phonon replicas indicate localization of excitons. With the help of the Huang-Rhys factor and the fraction of strongly localized excitons the depth of the localization potentials was estimated in good agreement with σ. Using the intensity of the Zn1−xCdxO-luminescence as function of the temperature the thermal activation energy of non-radiative processes has been determined.