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Proceedings Paper

Highly efficient AlGaN-based UV-LEDs and their application as visible light sources
Author(s): Toshio Nishida; Naoki Kobayashi
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Paper Abstract

AlGaN-based highly efficient ultraviolet light emitting diodes (UV-LEDs) are reported. To enhance radiative recombination by suppressing the effect of the internal polarization field, we introduced an AlGaN quantum well as thin as 8 molecular layers, at which the optical transition is kept spatially direct. To improve the transparency and conductivity of p-type cladding layers, we introduced a short-period alloy superlattice. For stronger carrier confinement, high-Al-content carrier blocking layers are introduced. Further, to reduce nonradiative centers, we used high-quality bulk GaN substrate obtained by hydride vapor phase epitaxy (HVPE). The resultant UV-LED performance is intrinsically ideal. The maximum output power is 10mW at the injection current of 400 mA in spite of the optically absorptive GaN substrate, and the estimated internal quantum efficiency is over 80% at the wavelength of 352 nm. This wavelength has affords efficient excitation of fluorescent materials. We also demonstrate simultaneous and equivalent excitation of fluorescence material of three basal colors by this UV-LED.

Paper Details

Date Published: 6 June 2002
PDF: 8 pages
Proc. SPIE 4641, Light-Emitting Diodes: Research, Manufacturing, and Applications VI, (6 June 2002); doi: 10.1117/12.469204
Show Author Affiliations
Toshio Nishida, NTT Basic Research Labs. (Japan)
Naoki Kobayashi, NTT Basic Research Labs. (Japan)

Published in SPIE Proceedings Vol. 4641:
Light-Emitting Diodes: Research, Manufacturing, and Applications VI
E. Fred Schubert; H. Walter Yao, Editor(s)

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