Regensburg 2010 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 21: Quantum Dots and Wires, Optical Properties I: Nitrides

HL 21.3: Talk

Tuesday, March 23, 2010, 10:00–10:15, H17

Microphotoluminescence Investigations of Single Group-III-Nitride Quantum Dots — •Stefan Werner, Christian Kindel, Thomas Switaiski, and Axel Hoffmann — Institut für Festkörperphysik, Technische Universität Berlin

The optical research of single InGaN quantum dots is difficult due to the fact that their emission lines are significantly broadened. The emission energies of wurtzite InGaN QDs are strongly influenced by fluctuating electric fields, resulting in line-width broadening. We present spatially- and time-resolved photoluminescence measurements of single InGaN/GaN quantum dots. Therefore, a new microphotoluminescence setup was built. In order to investigate the behavior of different excitonic complexes and their recombination dynamics, power, polarization and time-dependent measurements were performed. Some lines saturate at high-power excitation, giving an indication for exciton-like behavior. Others have a super-linear intensity increase. Those lines might be biexcitionic. Most emission lines showed a strong linear polarization but with different polarization angels. That fact helps to assign the lines to different quantum dots. The presented time-resolved PL measurements might give addional informations about the origin of the observed emission lines. For some lines, the decay time is increased by a factor of 2 in respect to other lines, indicating biexcitionic behavior.