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Open AccessArticle

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

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

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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