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Localization dynamics of biexcitons and electron–hole plasmas in GaN‐based mixed crystals
Author(s) -
Hirano Daisuke,
Tayagaki Takeshi,
Yamada Yoichi,
Kanemitsu Yoshihiko
Publication year - 2010
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.200982602
Subject(s) - biexciton , exciton , picosecond , photoluminescence , excited state , condensed matter physics , excitation , electron , atomic physics , materials science , physics , molecular physics , laser , optics , quantum mechanics
We report time‐resolved photoluminescence (PL) spectra in highly excited Al x Ga 1− x N mixed crystals under band‐to‐band excitation. The PL dynamics of excitons and biexcitons reveals that the localization of excitons begins within a few picoseconds delay time and almost all the excitons relax into the localized band‐tail states within 10 ps delay time after laser excitations. The biexciton formation time of ∼2 ps is extracted from the rise time of the PL intensities of excitons and biexcitons. These results indicate that biexcitons are formed from the free excitons and that the exciton localization, due to the potential fluctuations in the mixed crystals, reduces the exciton–exciton collisions and the formation of free biexcitons.