Phonon replica dynamics in high quality GaN epilayers and AlGaN/GaN quantum wells

We present an experimental study of the exciton and phonon replica dynamics in high quality GaN epilayers and AlGaN/GaN quantum wells (QW) by means of picosecond time-resolved photoluminescence (PL) measurements. A non-exponential decay is observed both at the zero phonon line (ZPL) and at the n = 1 LO replica. Time-resolved spectra unambiguously assign the replica to the free exciton A recombination. Optical migration effects are detected both in the epilayer and the QWs samples and disappear as the temperature increases up to 60-90 K. Even though the sample quality is comparable to state-of-the-art samples, localization effects dominate the exciton dynamics at low temperature in the studied GaN based strucures.


Published in:
Physica Status Solidi a-Applied Research, 183, 1, 129-134
Year:
2001
ISSN:
0031-8965
Keywords:
Laboratories:




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