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High‐efficiency UV LEDs using quaternary InAlGaN
Author(s) -
Hirayama Hideki,
Kyono Takashi,
Akita Katsushi,
Nakamura Takao,
Ishibashi Koji
Publication year - 2006
Publication title -
electrical engineering in japan
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.136
H-Index - 28
eISSN - 1520-6416
pISSN - 0424-7760
DOI - 10.1002/eej.20287
Subject(s) - light emitting diode , optoelectronics , materials science , ultraviolet , quantum efficiency , diode
Abstract High‐efficiency ultraviolet (UV) light sources are very attractive for application to the medical field, white lighting, high‐density memories, and so on. We have demonstrated that 300‐ to 370‐nm UV emission is considerably enhanced by the introduction of several percent of In into AlGaN due to an In‐segregation effect. We fabricated 310‐nm‐band UV LEDs with quaternary InAlGaN emitting layers on a sapphire substrate and obtained submilliwatt output power. We also fabricated 350‐nm‐band InAlGaN‐based quantum‐well LEDs on GaN substrates in order to eliminate the effects of threading dislocations. The maximum UV output power obtained was as high as 7.4 mW under room‐temperature CW operation. The maximum external quantum efficiency (EQE) was 1.1% with an injection current of 50 mA, which is the highest EQE ever obtained for 350‐nm‐band UV LEDs with top‐emission geometry. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 157(3): 43–51, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20287 Copyright © 2006 Wiley Periodicals, Inc.