Development of high performance green c-plane III-nitride light-emitting diodes

Abdullah. I. Alhassan, Nathan. G. Young, Robert. M. Farrell, Christopher. Pynn, Feng. Wu, Ahmed. Y. Alyamani, Shuji Nakamura, Steven. P. DenBaars, James. S. Speck

Research output: Contribution to journalArticlepeer-review

20 Scopus citations

Abstract

The effect of employing an AlGaN cap layer in the active region of green c-plane light-emitting diodes (LEDs) was studied. Each quantum well (QW) and barrier in the active region consisted of an InGaN QW and a thin Al0.30Ga0.70N cap layer grown at a relatively low temperature and a GaN barrier grown at a higher temperature. A series of experiments and simulations were carried out to explore the effects of varying the Al0.30Ga0.70N cap layer thickness and GaN barrier growth temperature on LED efficiency and electrical performance. We determined that the Al0.30Ga0.70N cap layer should be around 2 nm and the growth temperature of the GaN barrier should be approximately 75° C higher than the growth temperature of the InGaN QW to maximize the LED efficiency, minimize the forward voltage, and maintain good morphology. Optimized Al0.30Ga0.70N cap growth conditions within the active region resulted in high efficiency green LEDs with a peak external quantum efficiency (EQE) of 40.7% at 3 A/cm2. At a normal operating condition of 20 A/cm2, output power, EQE, forward voltage, and emission wavelength were 13.8 mW, 29.5%, 3.5 V, and 529.3 nm, respectively.
Original languageEnglish (US)
Pages (from-to)5591
JournalOptics Express
Volume26
Issue number5
DOIs
StatePublished - Feb 23 2018
Externally publishedYes

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

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