We report a polarized white light-emitting device that monolithically integrates an electrically injected blue light-emitting diode grown on the (2021) face of a bulk GaN substrate and optically pumped InGaN quantum wells (QWs) with green and red light emission grown on the (2021) face. To overcome the challenges associated with growing high indium content InGaN QWs for long wavelength emission, a p-i-n doping profile was used to red-shift the emission wavelength of one of the optically pumped QWs by creating a built-in electric field in the same direction as the polarization-induced electric field. Emission peaks were observed at 450 nm from the electrically injected QW and at 520 nm and 590 nm from the optically pumped QWs, which were situated in n-i-n and p-i-n structures, respectively. The optically pumped QW in the p-i-n structure was grown at a growth temperature that was 10 °C colder compared to the QW in the n-i-n structure, so the emission from the QW in the p-i-n structure was red-shifted due to increased indium content as well as the built-in electric field. Modeling work confirmed that the built-in electric field made a greater contribution than the change in alloy composition to the red-shift in emission from the QW in the p-i-n structure. The combined emission from the red, green, and blue QWs resulted in white-light emission with Commission Internationale de l'Eclairage x- and y-chromaticity coordinates of (0.33, 0.35) and an optical polarization ratio of 0.30.
|Original language||English (US)|
|Journal||JOURNAL OF APPLIED PHYSICS|
|State||Published - Jul 15 2016|
Bibliographical noteKAUST Repository Item: Exported on 2022-06-02
Acknowledgements: This work was supported by the Solid State Lighting and Energy Electronics Center (SSLEEC) and the KACST-KAUST-UCSB Solid State Lighting Program (SSLP). A portion of this work was done in the UCSB nanofabrication facility, part of the NSF funded National Nanotechnology Infrastructure Network (ECS-03357650). This work made use of the MRL Central Facilities at UCSB supported by the MRSEC Program of the NSF under Award No. DMR 1121053. C. D. Pynn was supported by the National Science Foundation Graduate Research Fellowship Program under Grant No. DGE 1144085. The authors would like to thank the contributors to the open source Python color science package Colour, which is freely distributed under the New BSD License and was used to generate the CIE diagram as well as calculate CIE coordinates, CCT, and CRI. The authors also thank Dr. Tom Mates for performing SIMS characterization and Karthik Krishnaswamy for helpful discussion.
This publication acknowledges KAUST support, but has no KAUST affiliated authors.
ASJC Scopus subject areas
- Physics and Astronomy(all)