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Anisotropy of the In‐Plane Strain in GaN Grown on A‐Plane Sapphire
Author(s) -
Paskov P.P.,
Darakchieva V.,
Paskova T.,
Holtz P.O.,
Monemar B.
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<892::aid-pssb892>3.0.co;2-t
Subject(s) - sapphire , anisotropy , materials science , isotropy , epitaxy , condensed matter physics , strain (injury) , photoluminescence , relaxation (psychology) , diffraction , layer (electronics) , plane (geometry) , exciton , crystallography , substrate (aquarium) , optics , optoelectronics , chemistry , composite material , laser , physics , geometry , geology , medicine , psychology , social psychology , mathematics , oceanography
A comparative study of GaN layer grown by hydride vapour phase epitaxy on A ‐plane sapphire before and after removal of the substrate is presented. A large anisotropy of the in‐plane strain in the as‐grown sample is revealed by X‐ray diffraction measurements and polarized photoluminescence. The strain anisotropy is found to modify the selection rules for the transitions leading to a splitting of the optically active states of the A and B excitons. Almost complete strain relaxation and recovery of the optical isotropy in the (0001) plane is observed in the free‐standing layer.