: Received: 11 September 2017 / Approved: 12 September 2017 / Online: 12 September 2017 (05:31:24 CEST)
: Received: 12 September 2017 / Approved: 12 September 2017 / Online: 12 September 2017 (10:06:36 CEST)
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. Materials2017, 10, 1323.
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.
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.
InGaN green LEDs; active region non-uniformity; temperature-dependent electroluminescence; internal quantum efficiency; light extraction efficiency; extended defects; modeling
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