Dresden 2011 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 57: ZnO: Optical Properties
HL 57.2: Talk
Wednesday, March 16, 2011, 14:45–15:00, POT 151
Time-resolved photoluminescence spectroscopy of ZnO / (ZnMg)O heterostructures — •Verena Bornwasser1, Alexej Chernikov1, Martin Koch1, Sangam Chatterjee1, Stephan W. Koch1, Bernhard Laumer2, and Martin Eickhoff3 — 1Department of Physics and Material Sciences Center, Philipps-Universität Marburg, Renthof 5, D 35032 Marburg — 2Walter Schottky Institut, Technische Universität München, Am Coulombwall 4, D 85748 Garching — 3Physikalisches Institut, Justus-Liebig-Universität Giessen, Heinrich-Buff-Ring 16, D 35392 Giessen
ZnO-based materials are promising for the realization of optoelectronic devices operating in the UV. ZnO has a band gap energy of about 3.4eV, a large exciton binding energy of 60meV and a high material quality due to recently improved growth methods. Hence, a detailed understanding of the optical properties and carrier dynamics in this system is crucial to further optimize growth procedures and device performance. Here we present time-resolved photoluminescence measurements of the hetero- and homoepitaxially grown ZnO quantum wells and (ZnMg)O barrier layers. Our results show a strong correlation between the substrate and the material quality for the quantum well system. In the case of the (ZnMg)O barriers, post-growth annealing significantly improves the material quality. In addition a structural phase separation is observed as the annealing temperature exceeds 950°C.