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HL: Fachverband Halbleiterphysik

HL 31: Poster: Nitrides

HL 31.8: Poster

Monday, March 31, 2014, 17:00–20:00, P2

Photoreflectance studies on InGaN/GaN multi-quantum well structures — •Stefan Freytag¹, Christoph Berger¹, Pavel Y. Bokov², Armin Dadgar¹, Rüdiger Goldhahn¹, Alois Krost¹, and Martin Feneberg¹ — ¹Institut für Experimentelle Physik , Otto-von-Guericke-Universität, Magdeburg, Germany — ²Moscow State University, Moscow, Russia

Wurtzite(0001) oriented InGaN/GaN multi-quantum well structures were investigated by photoreflectance spectroscopy at variable temperatures. To achieve a systematic understanding, structures were varied from sample to sample, i.e. quantum well thickness, barrier thickness, number of quantum wells and the width of the cap layer. We clearly observe free excitons in the GaN matrix and find a very prominent photoreflectance feature from the InGaN quantum wells. The energy position of this contribution as a function of temperature is compared to photoluminescence yielding data on localization effects. Finally, additional features in photoreflectance which are located energetically between the quantum wells and the GaN excitons are found and possible origins are discussed.