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Exciton localization in InGaN/GaN single quantum well structures
Author(s) -
Graham D. M.,
Vala A. Soltani,
Dawson P.,
Godfrey M. J.,
Kappers M. J.,
Smeeton T. M.,
Barnard J. S.,
Humphreys C. J.,
Thrush E. J.
Publication year - 2003
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.200303338
Subject(s) - photoluminescence , exciton , indium , phonon , quantum well , materials science , condensed matter physics , spectral line , coupling (piping) , gaussian , optoelectronics , physics , optics , quantum mechanics , laser , metallurgy
We have performed a detailed investigation of the low temperature ( T = 6 K) photoluminescence spectra and recombination lifetimes of localized excitons in a set of InGaN/GaN single quantum wells in which the indium fraction in the quantum well was varied. We found that with increasing indium fraction the photoluminescence peak emission moved to lower energy and the intensities of the phonon replicas relative to the zero‐phonon line increased. From a multi‐Gaussian fit of the experimental data, we extracted the Huang–Rhys factor ( S ), a measure of the strength of the exciton coupling with LO‐phonons. By comparing experimental S factors with the results of a theoretical model, we found that the excitons localize on a length scale of ∼2 nm in our samples. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)