True Yellow Light-Emitting Diodes as Phosphor for Tunable Color-Rendering Index Laser-Based White Light

Bilal Janjua, Tien Khee Ng, Chao Zhao, Aditya Prabaswara, Giuseppe Bernardo Consiglio, Davide Priante, Chao Shen, Rami T. Elafandy, Dalaver H. Anjum, Abdullah A. Alhamoud, Abdullah A. Alatawi, Yang Yang, Ahmed Y. Alyamani, Munir M. El-Desouki, Boon S. Ooi

Research output: Contribution to journalArticlepeer-review

20 Scopus citations

Abstract

An urgent challenge for the lighting research community is the lack of efficient optical devices emitting in between 500 and 600 nm, resulting in the “green-yellow gap”. In particular, true green (∼555 nm) and true yellow (∼590 nm), along with blue and red, constitute four technologically important colors. The III-nitride material system, being the most promising choice of platform to bridge this gap, still suffers from high dislocation density and poor crystal quality in realizing high-power, efficient devices. Particularly, the high polarization fields in the active region of such 2D quantum confined structures prevent efficient recombination of carriers. Here we demonstrate a true yellow nanowire (NW) light emitting diode (LED) with peak emission of 588 nm at 29.5 A/cm2 (75 mA in a 0.5 × 0.5 mm2 device) and a low turn-on voltage of ∼2.5 V, while having an internal quantum efficiency of 39%, and without “efficiency droop” up to an injection current density of 29.5 A/cm2. By mixing yellow light from a NW LED in reflective configuration with that of a red, green, and blue laser diode (LD), white light with a correlated color temperature of ∼6000 K and color-rendering index of 87.7 was achieved. The nitride-NW-based device offers a robust, long-term stability for realizing yellow light emitters for tunable color-rendering index solid-state lighting, on a scalable, low-cost, foundry-compatible titanium/silicon substrate, suitable for industry uptake.
Original languageEnglish (US)
Pages (from-to)2089-2095
Number of pages7
JournalACS Photonics
Volume3
Issue number11
DOIs
StatePublished - Oct 25 2016

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