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Effect of Al incorporation in nonpolar m ‐plane GaN/AlGaN multi‐quantum‐wells using plasma‐assisted molecular‐beam epitaxy
Author(s) -
Lim Caroline B.,
Ajay Akhil,
Bougerol Catherine,
BelletAmalric Edith,
Schörmann Jörg,
Beeler Mark,
Monroy Eva
Publication year - 2017
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.201600849
Subject(s) - molecular beam epitaxy , materials science , alloy , stacking , quantum well , anisotropy , surface finish , surface roughness , mole fraction , plane (geometry) , morphology (biology) , optoelectronics , condensed matter physics , epitaxy , optics , nanotechnology , composite material , chemistry , geometry , layer (electronics) , physics , geology , paleontology , laser , organic chemistry , mathematics
This paper assesses the difficulties associated with Al incorporation in nonpolar m ‐plane GaN/AlGaN multi‐quantum‐wells grown on free‐standing m ‐plane GaN. Structures with average Al mole fraction below 6% show atomically flat surfaces and no extended structural defects, in spite of alloy fluctuations up to 30% of the average concentration. Increasing the average Al composition of the alloy above 23% induces anisotropic degradation of the surface morphology, with appearance of elongated features which increase the surface roughness, along with formation of stacking faults, dislocations, and nm‐sized Al‐rich clusters. The effect of all these structural features on the MQWs optical performance is discussed.