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Optical Characterization of Al x Ga 1—x N Alloys (x < 0.7) Grown on Sapphire or Silicon
Author(s) -
Leroux M.,
Dalmasso S.,
Natali F.,
Helin S.,
Touzi C.,
Laügt S.,
Passerel M.,
Omnes F.,
Semond F.,
Massies J.,
Gibart P.
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<887::aid-pssb887>3.0.co;2-d
Subject(s) - bowing , photoluminescence , luminescence , sapphire , materials science , silicon , exciton , stokes shift , alloy , band gap , valence (chemistry) , reflectivity , condensed matter physics , analytical chemistry (journal) , optics , optoelectronics , chemistry , physics , laser , metallurgy , philosophy , theology , organic chemistry , chromatography
The optical properties of Al x Ga 1— x N samples ( x < 0.7) have been studied by photoluminescence (PL) and reflectivity in the 10–300 K temperature range. Various physical properties have been studied as a function of composition, such as Stokes shift, alloy broadening, exciton localization, and Huang–Rhys factor. Up to x ≈ 0.3, a band gap bowing factor of ∼0.9 eV accounts for the variation of PL and reflectivity energies. At higher compositions, luminescence energies deepen with regard to this behaviour. This is interpreted as a consequence of the Γ 9 – Γ 7 crossover of the valence band maxima. This is confirmed by the linear polarization of the luminescence studied under oblique observation.