Influence of the barrier composition on the light output of InGaN multiple-quantum-well ultraviolet light emitting diodes

Author(s):  
A. Knauer ◽  
V. Kueller ◽  
S. Einfeldt ◽  
V. Hoffmann ◽  
T. Kolbe ◽  
...  
2003 ◽  
Vol 83 (17) ◽  
pp. 3456-3458 ◽  
Author(s):  
JianPing Zhang ◽  
Shuai Wu ◽  
Shiva Rai ◽  
Vasavi Mandavilli ◽  
Vinod Adivarahan ◽  
...  

2003 ◽  
Vol 764 ◽  
Author(s):  
X. A. Cao ◽  
S. F. LeBoeuf ◽  
J. L. Garrett ◽  
A. Ebong ◽  
L. B. Rowland ◽  
...  

Absract:Temperature-dependent electroluminescence (EL) of InGaN/GaN multiple-quantum-well light-emitting diodes (LEDs) with peak emission energies ranging from 2.3 eV (green) to 3.3 eV (UV) has been studied over a wide temperature range (5-300 K). As the temperature is decreased from 300 K to 150 K, the EL intensity increases in all devices due to reduced nonradiative recombination and improved carrier confinement. However, LED operation at lower temperatures (150-5 K) is a strong function of In ratio in the active layer. For the green LEDs, emission intensity increases monotonically in the whole temperature range, while for the blue and UV LEDs, a remarkable decrease of the light output was observed, accompanied by a large redshift of the peak energy. The discrepancy can be attributed to various amounts of localization states caused by In composition fluctuation in the QW active regions. Based on a rate equation analysis, we find that the densities of the localized states in the green LEDs are more than two orders of magnitude higher than that in the UV LED. The large number of localized states in the green LEDs are crucial to maintain high-efficiency carrier capture at low temperatures.


2019 ◽  
Vol 9 (5) ◽  
pp. 871 ◽  
Author(s):  
Abu Islam ◽  
Dong-Soo Shim ◽  
Jong-In Shim

We investigate the differences in optoelectronic performances of InGaN/AlGaN multiple-quantum-well (MQW) near-ultraviolet light-emitting diodes by using samples with different indium compositions. Various macroscopic characterizations have been performed to show that the strain-induced piezoelectric field (FPZ), the crystal quality, and the internal quantum efficiency increase with the sample’s indium composition. This improved performance is owing to the carrier recombination at relatively defect-free indium-rich localized sites, caused by the local in-plane potential-energy fluctuation in MQWs. The potential-energy fluctuation in MQWs are considered to be originating from the combined effects of the inhomogeneous distribution of point defects, FPZ, and indium compositions.


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