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Impact of dislocations and defects on the relaxation behavior of InGaN/GaN multiple quantum wells grown on Si and sapphire substrates
Author(s) -
Yoshida Hisashi,
Hikosaka Toshiki,
Nago Hajime,
Nunoue Shinya
Publication year - 2015
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.201451585
Subject(s) - sapphire , materials science , optoelectronics , dislocation , relaxation (psychology) , stress relaxation , layer (electronics) , epitaxy , blueshift , quantum well , photoluminescence , nanotechnology , optics , composite material , laser , psychology , social psychology , creep , physics
We investigated the relaxation behavior of InGaN/GaN blue multiple quantum wells (MQWs) grown on Si (111) and sapphire (0001) substrates to determine how the threading dislocation density (TDD) in the underlying GaN layer, the thickness of the MQWs, and the growth substrate (Si or sapphire) affect the relaxation behavior of MQWs. The results demonstrate that the value of the in‐plane lattice parameter difference between MQWs and GaN (IPLD MQWs–GaN ) is strongly dependent on the TDD in the underlying GaN layer. The thickness of the InGaN well layer has the greatest effect on the IPLD MQWs–GaN value of the blue MQW structure: a thin InGaN well layer with high In content is more effective than a thick InGaN well layer with low In content for obtaining high‐quality blue MQWs without misfit dislocations (MDs). Furthermore, MQWs grown on Si are likely to contain MDs and unlikely to form V‐defects, whereas the opposite tendency is true of MQWs grown on sapphire. Using threading dislocations, MDs, and V‐defects, we propose relaxation mechanisms for MQWs grown on Si (111) and sapphire (0001) substrates.