Quantum Efficiency Enhancement of a GaN-Based Green Light-Emitting Diode by a Graded Indium Composition p-Type InGaN Layer

To improve the internal quantum efficiency of green light-emitting diodes, we present the numerical design and analysis of bandgap-engineered W-shaped quantum well. The numerical results suggest significant improvement in the internal quantum efficiency of the proposed W-LED. The improvement is associated with significantly improved hole confinement due to the localization of indium in the active region, leading to improved radiative recombination rate. In addition, the proposed device shows reduced defect-assisted Shockley-Read-Hall (SRH) recombination rate as well as Auger recombination rate. Moreover, the efficiency rolloff in the proposed device is associated with increased built-in electromechanical field.

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High Internal Quantum Efficiency Blue-Green Light-Emitting Diode with Small Efficiency Droop Fabricated on Low Dislocation Density GaN Substrate

Japanese Journal of Applied Physics ◽

10.7567/jjap.52.08jk09 ◽

2013 ◽

Vol 52 (8S) ◽

pp. 08JK09 ◽

Cited By ~ 13

Author(s):

Tomotaka Sano ◽

Tomohiro Doi ◽

Shunko Albano Inada ◽

Tomohiko Sugiyama ◽

Yoshio Honda ◽

...

Keyword(s):

Dislocation Density ◽

Quantum Efficiency ◽

Light Emitting Diode ◽

Internal Quantum Efficiency ◽

Green Light ◽

Efficiency Droop ◽

Light Emitting ◽

Low Dislocation Density

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Study on Optical Properties and Internal Quantum Efficiency Measurement of GaN-based Green LEDs

Applied Sciences ◽

10.3390/app9030383 ◽

2019 ◽

Vol 9 (3) ◽

pp. 383

Author(s):

Boyang Lu ◽

Lai Wang ◽

Zhibiao Hao ◽

Yi Luo ◽

Changzheng Sun ◽

...

Keyword(s):

Optical Properties ◽

Quantum Efficiency ◽

Light Emitting Diode ◽

Internal Quantum Efficiency ◽

Green Light ◽

Excitation Power ◽

Temperature Dependent ◽

Light Emitting ◽

Integrated Intensity ◽

Calculation Results

In this paper, the optical properties of GaN-based green light emitting diode (LED) are investigated and the internal quantum efficiency (IQE) values are measured by temperature dependent photoluminescence (TDPL) and power dependent photoluminescence (PDPL) methods. The "S-shaped” shift of peak wavelength measured at different temperature disappears gradually and the spectra broadening can be observed with increasing excitation power. The IQE calculation results of TDPL, which use the integrated intensity measured at low temperature as unity, can be modified by PDPL in order to acquire more accurate IQE values.

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Loss of Quantum Efficiency in Green Light Emitting Diode Dies at Low Temperature

MRS Proceedings ◽

10.1557/proc-0955-i15-12 ◽

2006 ◽

Vol 955 ◽

Author(s):

Yufeng Li ◽

Wei Zhao ◽

Yong Xia ◽

Mingwei Zhu ◽

Jayantha Senawiratne ◽

...

Keyword(s):

Low Temperature ◽

Quantum Efficiency ◽

Light Emitting Diode ◽

Multiple Quantum Well ◽

Green Light ◽

Secondary Emission ◽

Multiple Quantum ◽

Acceptor Pair ◽

Light Emitting ◽

Lower Temperature

ABSTRACTThe electroluminescence, photoluminescence and cathodoluminescence of GaInN/GaN multiple quantum well light emitting diode dies are analyzed at variable low temperature. Three dies of nominally identical structure but strongly different RT performance from 510 nm to 525 nm have been studied. The electroluminescence peak energy exhibits a blue shift from RT to 158 K followed by a red shift for lower temperature. In the same low-temperature range, a secondary emission peak appears near 390 nm (3.18 eV) that resembles a donor-acceptor pair transition from GaN. Depth profiling spectroscopy of this transition at 77 K reveals its location either in the unintentionally doped quantum barriers or within the n-GaN layer, rather than the commonly believed Mg doped p-type GaN layers. The external quantum efficiency of each die increases as the temperature is lowered. A maximum is reached for all near 158 K while for lower temperature as low as 7.7 K, the efficiency continuously drops. The pronounced efficiency maximum is tentatively assigned to a combination of temperature dependent mobility and shift of the actual pn-junction location.

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