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Various misfit dislocations in green and yellow GaInN/GaN light emitting diodes
Author(s) -
Zhu Mingwei,
You Shi,
Detchprohm Theeradetch,
Paskova Tanya,
Preble Edward A.,
Wetzel Christian
Publication year - 2010
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.200983645
Subject(s) - materials science , light emitting diode , optoelectronics , electroluminescence , dislocation , sapphire , epitaxy , diode , quantum well , substrate (aquarium) , wavelength , relaxation (psychology) , optics , layer (electronics) , nanotechnology , laser , physics , composite material , oceanography , psychology , social psychology , geology
We report the growth and structural characteristics of green and yellow (529–576 nm) GaInN/GaN light emitting diodes (LEDs) grown on two types of c ‐plane substrates – bulk GaN and sapphire. In this longer wavelength range, depending on the substrate, we find different strain relaxation mechanisms within the GaInN/GaN quantum well (QW) region. In optimized epitaxy, structures on sapphire that contain a low density of threading dislocations (TDs) within the n ‐GaN show virtually no generation of additional misfit dislocations (MDs) (<10 8 cm −2 ) or V ‐defects within the QW region for emission wavelengths up to 571 nm. On bulk GaN substrate, however, where much fewer TDs reach the QWs, strain relaxation is observed by inclined dislocation pairs in green emitters and a high density of edge‐type MDs in yellow emitters. The electroluminescence line width, as well as the efficiency droop, was found to increase with dislocation density in the QWs.