High-color-rendering-index phosphor-free InGaN-based white light-emitting diodes by carrier injection enhancement via V-pits

Daisuke Iida,Zhe Zhuang,Pavel Kirilenko,Kazuhiro Ohkawa,Martin Velazquez-Rizo

doi:10.1063/5.0026017

Abstract

We herein report the growth of phosphor-free InGaN-based white light-emitting diodes (LEDs) by metalorganic vapor-phase epitaxy. The active region consists of blue and red InGaN quantum wells (QWs). To improve the current injection and generate broadband emission, the V-pit structures in the LEDs were fabricated intentionally before growing the QWs. The monolithic white LEDs emit in the range of 410–770 nm and, by tuning the injection current, can cover correlated color temperature (CCT) values corresponding to warm white, natural white, and cool white. The color-rendering index (CRI) of the white LEDs reaches 88 at an injection current of 10 mA. At an injection current of 30 mA, the white LEDs exhibit the chromaticity coordinates of (0.320 and 0.334) in the Commission Internationale de l'Eclairage 1931 chromaticity diagram, a CRI of 78, and a CCT of 6110 K.

Highlights

The blue or violet light-emitting diodes (LEDs) serve to optically pump the phosphors, converting part of the LED emission to longer wavelengths via phosphor re-emission
The monolithic white LEDs emit in the range of 410–770 nm and, by tuning the injection current, can cover correlated color temperature (CCT) values corresponding to warm white, natural white, and cool white
By tuning the alloy composition of III-nitride materials, they can be made to emit over the full visible spectrum, which makes them excellent candidates for monolithically integrated white LEDs with polychromatic emission

Summary

Introduction

The blue or violet LEDs serve to optically pump the phosphors, converting part of the LED emission to longer wavelengths via phosphor re-emission. ABSTRACT We report the growth of phosphor-free InGaN-based white light-emitting diodes (LEDs) by metalorganic vapor-phase epitaxy. To improve the current injection and generate broadband emission, the V-pit structures in the LEDs were fabricated intentionally before growing the QWs. The monolithic white LEDs emit in the range of 410–770 nm and, by tuning the injection current, can cover correlated color temperature (CCT) values corresponding to warm white, natural white, and cool white.

Results

Conclusion