Open AccessHeteroepitaxy of AlGaN on bulk AlN substrates for deep ultraviolet light emitting diodes
Author(s) -
Zhengru Ren,
Qian Sun,
SoonYong Kwon,
Jung Han,
Kristina Davitt,
YoonKyu Song,
A. V. Nurmikko,
Hyung Koun Cho,
W. Liu,
J. Smart,
L. J. Schowalter
Publication year - 2007
Publication title -
applied physics letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.182
H-Index - 442
eISSN - 1077-3118
pISSN - 0003-6951
DOI - 10.1063/1.2766841
Subject(s) - materials science , light emitting diode , optoelectronics , sapphire , nucleation , wide bandgap semiconductor , ultraviolet , stress relaxation , substrate (aquarium) , nitride , dislocation , diode , composite material , optics , layer (electronics) , laser , chemistry , physics , creep , organic chemistry , oceanography , geology
The authors report the growth of AlGaN epilayers and deep ultraviolet (UV) light emitting diodes (LEDs) on bulk AlN substrates. Heteroepitaxial nucleation and strain relaxation are studied through controlled growth interruptions. Due to a low density of preexisting dislocations in bulk AlN, the compressive strain during AlGaN heteroepitaxy cannot be relieved effectively. The built-up of strain energy eventually induces either an elastic surface roughening or plastic deformation via generation and inclination of dislocations, depending on the stressor interlayers and growth parameters used. AlGaN LEDs on bulk AlN exhibit noticeable improvements in performance over those on sapphire, pointing to a promising substrate platform for III-nitride UV optoelectronics.open352
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