Regensburg 2010 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 38: ZnO and Related Semiconductors
HL 38.13: Talk
Wednesday, March 24, 2010, 12:45–13:00, H17
Temperature-dependent time-resolved photoluminescence on MgZnO — •Alexander Müller, Marko Stölzel, Christof Dietrich, Gabriele Benndorf, Michael Lorenz, and Marius Grundmann — Universität Leipzig, Institut für Exp. Physik II, Abteilung Halbleiterphysik, Linnéstraße 5, 04103 Leipzig
ZnO is a promising material for optoelectronic applications in the UV spectral range. By alloying it with MgO, the band gap of the resulting MgZnO can be increased, making it a suitable barrier layer for ZnO-based quantum wells. To investigate the dynamic carrier properties in this material, we have performed time-resolved photoluminescence (TRPL) measurements on PLD-grown MgxZn1−xO thin films with x ≤ 0.33. Carrier thermalization and localization effects have been investigated by temperature-dependent TRPL measurements. At low temperatures, the excitons in this alloy are strongly localized. For samples with low Mg concentration, the spectrum is dominated by impurity-bound excitons exhibiting a fast decay. For large Mg contents, the excitons are mainly localized in randomly distributed alloy-potential minima, showing a slow, non-exponential decay process. With increasing temperatures, the decay time strongly decreases, indicating a transfer of the excitons to non-localized, free states. This explanation will be supported by Monte Carlo simulations.