Open AccessInfluence of pillar-and hole-patterned sapphire substrates on MOVPE grown GaN bulk and LED structures
Author(s) -
Yang Jiang,
Yi Luo,
Lai Wang,
Hongtao Li,
Guangyi Xi,
Wei Zhao,
Yu Han
Publication year - 2009
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.58.3468
Subject(s) - sapphire , materials science , metalorganic vapour phase epitaxy , optoelectronics , scanning electron microscope , substrate (aquarium) , pillar , diffraction , atomic force microscopy , optics , layer (electronics) , nanotechnology , epitaxy , composite material , laser , oceanography , physics , structural engineering , engineering , geology
Bulk GaN material and LED structures on pillar-patterned sapphire substrates PSS-p and hole-patterned sapphire substrates PSS-h were grown by MOCVD and the characteristic was compared in detail. X-ray diffraction and atomic force microscope measurements show a better crystal quality and surface morphology of GaN on PSS-h than that of GaN on PSS-p, which is due to the lateral growth of GaN on PSS-h observed from cross-sectional scanning electron microscopy. Furthermore, the output power of LED on PSS-p and PSS-h with 20 mA injection current are 46% and 33% higher than LED on conventional sapphire substrate, respectively. The temperature-dependent photoluminesence measurements indicate that the internal quantum efficiencies of all samples are quite close. Therefore, the airgaps between GaN and PSS-h act against the improvement of light extraction efficiency.