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

• DOI: 10.1021/acsphotonics.6b00457
• Publication Date: 2016-10-11T20:32:08Z
• Authors: Bilal Janjua; Tien Khee Ng; Chao Zhao; Aditya Prabaswara; Giuseppe Bernardo...; 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
• Keywords: Color rendering index; Solid-State Lighting; Quantum Efficiency

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