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標題: Defect reduction and efficiency improvement of near-ultraviolet emitters via laterally overgrown GaN on a GaN/patterned sapphire template
作者: Wuu, D.S.
Wang, W.K.
Wen, K.S.
Huang, S.C.
Lin, S.H.
Huang, S.Y.
Lin, C.F.
Horng, R.H.
關鍵字: vapor-phase epitaxy;light-emitting-diodes;patterned sapphire;grown;gan;density;films
Project: Applied Physics Letters
期刊/報告no:: Applied Physics Letters, Volume 89, Issue 16.
An approach to improve the defect density and internal quantum efficiency of near-ultraviolet emitters was proposed using a combination of epitaxial lateral overgrowth (ELOG) and patterned sapphire substrate (PSS) techniques. Especially, a complementary dot array pattern corresponding to the underlying PSS was used for the ELOG-SiO2 mask design. Based on the transmission-electron-microscopy and etch-pit-density results, the ELOG/SiO2/GaN/PSS structure can reduce the defect density to a level of 10(5) cm(-2). The internal quantum efficiency of the InGaN-based ELOG-PSS light-emitting diode (LED) sample showed three times in magnitude as compared with that of the conventional GaN/sapphire one. Under a 20 mA injection current, the output powers of ELOG-PSS, PSS, and conventional LED samples were measured to be 3.3, 2.9, and 2.5 mW, respectively. The enhanced output power could be due to a combination of the reduction in dislocation density (by ELOG) and improved light extraction efficiency (by PSS). Unlike the previous double ELOG approaches, the presented ELOG-PSS structure needs only one regrowth process and will have high potential in future high-quality ultraviolet emitters, even blue/green laser diode applications. (c) 2006 American Institute of Physics.
ISSN: 0003-6951
DOI: 10.1063/1.2363148
Appears in Collections:材料科學與工程學系

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