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Materials 2017, 10(11), 1323; https://doi.org/10.3390/ma10111323

Efficiency of True-Green Light Emitting Diodes: Non-Uniformity and Temperature Effects

1
Ostendo Technologies Inc., 6185 Paseo del Norte, Carlsbad, CA 92011, USA
2
Optoelectronics and Biomedical Photonics Group, Aston Institute of Photonic Technologies, Aston University, Birmingham B4 7ET, UK
3
STR Group—Soft-Impact, Ltd., P.O. Box 83, 27 Engels Ave., 194156 Saint-Petersburg, Russia
4
Nanoscale Physics Research Laboratory, School of Physics and Astronomy, University of Birmingham, Birmingham B15 2TT, UK
*
Author to whom correspondence should be addressed.
Received: 17 August 2017 / Revised: 11 September 2017 / Accepted: 12 September 2017 / Published: 18 November 2017
(This article belongs to the Special Issue Light Emitting Diodes and Laser Diodes: Materials and Devices)
View Full-Text   |   Download PDF [2365 KB, uploaded 18 November 2017]   |  

Abstract

External quantum efficiency of industrial-grade green InGaN light-emitting diodes (LEDs) has been measured in a wide range of operating currents at various temperatures from 13 K to 300 K. Unlike blue LEDs, the efficiency as a function of current is found to have a multi-peak character, which could not be fitted by a simple ABC-model. This observation correlated with splitting of LED emission spectra into two peaks at certain currents. The characterization data are interpreted in terms of non-uniformity of the LED active region, which is tentatively attributed to extended defects like V-pits. We suggest a new approach to evaluation of temperature-dependent light extraction and internal quantum efficiencies taking into account the active region non-uniformity. As a result, the temperature dependence of light extraction and internal quantum efficiencies have been evaluated in the temperature range mentioned above and compared with those of blue LEDs. View Full-Text
Keywords: InGaN green LEDs; active region non-uniformity; temperature-dependent electroluminescence; internal quantum efficiency; light extraction efficiency; extended defects; modeling InGaN green LEDs; active region non-uniformity; temperature-dependent electroluminescence; internal quantum efficiency; light extraction efficiency; extended defects; modeling
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This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. (CC BY 4.0).
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Titkov, I.E.; Karpov, S.Y.; Yadav, A.; Mamedov, D.; Zerova, V.L.; Rafailov, E. Efficiency of True-Green Light Emitting Diodes: Non-Uniformity and Temperature Effects. Materials 2017, 10, 1323.

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