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Pressure Coefficients of the Light Emission in Cubic InGaN Epilayers and Cubic InGaN/GaN Quantum Wells
Author(s) -
Suski T.,
Teisseyre H.,
Łepkowski S.P.,
Perlin P.,
Kitamura T.,
Ishida Y.,
Okumura H.,
Chichibu SF.
Publication year - 2002
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 - 10.1002/1521-3951(200212)234:3<759::aid-pssb759>3.0.co;2-l
Subject(s) - wurtzite crystal structure , quantum well , photoluminescence , materials science , hydrostatic pressure , condensed matter physics , gallium nitride , indium gallium nitride , hexagonal crystal system , optoelectronics , optics , crystallography , physics , nanotechnology , chemistry , laser , layer (electronics) , thermodynamics
We have studied influence of hydrostatic pressure on the light emission from cubic InGaN/GaN quantum wells (QWs) and cubic InGaN thick epilayers. A qualitative difference between pressure dependence of photoluminescence peak energies for cubic and wurtzite symmetry InGaN/GaN QWs was found. Cubic samples revealed magnitude of d E E /d P of 26–30 meV/GPa, practically independent of the QW width. Previous studies of the hexagonal InGaN/GaN structures showed a drastic drop of d E E /d P with increasing QW width. This different behavior of two types of QWs is explained by the lack of built‐in electric field (along growth direction) in case of cubic structures. To describe pressure evolution of the optical transitions in cubic InGaN/GaN QWs, we use a simple k · p model based on the linear theory of elasticity. To reproduce the experimental data it is necessary to invoke presence of In‐rich fluctuations in the studied samples. In contrast to QWs, thick epilayers of cubic InGaN exhibit the anomalously small d E E /d P . We suggest mechanisms causing likely this effect.