scholarly journals Carrier Dynamics in InGaN/GaN-Based Green LED under Different Excitation Sources

Crystals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1061
Author(s):  
Jianfei Li ◽  
Duo Chen ◽  
Kuilong Li ◽  
Qiang Wang ◽  
Mengyao Shi ◽  
...  
Keyword(s):  
Room Temperature ◽  
Multiple Quantum Well ◽  
Excitation Power ◽  
Carrier Dynamics ◽  
Multiple Quantum ◽  
Light Emitting ◽  
Peak Energy ◽  
Measurement Results ◽  
Green Led ◽  
Electrical Generation

The excitation power and temperature dependence of the photoluminescence (PL) and electroluminescence (EL) spectra were studied in green InGaN/GaN multiple quantum well (MQW)-based light-emitting diodes (LED). An examination of the PL-325, PL-405, and EL spectra at identical optical or electrical generation rates at room temperature showed that the normalized spectra exhibited different characteristic peaks. In addition, the temperature behavior of the peak energy was S-shaped for the PL-405 spectrum, while it was V-shaped for the EL spectrum. These measurement results demonstrate that the excitation source can affect the carrier dynamics about the generation (injection), transfer, and distribution of carriers.

Luminescence Dynamics and Structural Investigation of InGaN/GaN Multiple Quantum Well Light Emitting Diodes

2011 ◽  
Vol 216 ◽  
pp. 445-449
Author(s):  
Zhen Sheng Lee ◽  
Ling Min Kong ◽  
Zhe Chuan Feng ◽  
Gang Li ◽  
Hung Lin Tsai ◽  
...  
Keyword(s):  
Quantum Well ◽  
Stokes Shift ◽  
Multiple Quantum Well ◽  
Blue Emission ◽  
Multiple Quantum ◽  
Spectroscopic Techniques ◽  
Time Resolved ◽  
Light Emitting ◽  
Indium Composition ◽  
Measurement Results

Luminescence properties of blue emission InGaN/GaN multiple quantum well (MQW) have been studied by temperature dependent photoluminescence (PL), photoluminescence excitation (PLE) and time-resolved photoluminescence (TRPL) spectroscopic techniques. Two typical samples are studied, both consisting of five periods of InGaN wells with different indium compositions of 21% and 24%, respectively. According to the PL and PLE measurement results, large values of activation energy and Stokes’ shift are obtained. This indicates that higher Indium composition results in an increase of composition fluctuation in the InGaN MQW region, showing the stronger carrier localization effect. The lifetime at the low-energy side of the InGaN peaks is longer for higher indium composition, as expected from the larger Stokes shift.

scholarly journals Internal quantum efficiency improvement of InGaN/GaN multiple quantum well green light-emitting diodes

2016 ◽  
Vol 24 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Q. Zhou ◽  
M. Xu ◽  
H. Wang
Keyword(s):  
Quantum Well ◽  
Quantum Efficiency ◽  
Light Emitting Diode ◽  
Internal Quantum Efficiency ◽  
Multiple Quantum Well ◽  
Visible Light Communication ◽  
Multiple Quantum ◽  
Internal Electric Field ◽  
Light Emitting ◽  
Green Led

In recent years, GaN-based light-emitting diode (LED) has been widely used in various applications, such as RGB lighting system, full-colour display and visible-light communication. However, the internal quantum efficiency (IQE) of green LEDs is significantly lower than that of other visible spectrum LED. This phenomenon is called “green gap”. This paper briefly describes the physical mechanism of the low IQE for InGaN/GaN multiple quantum well (MQW) green LED at first. The IQE of green LED is limited by the defects and the internal electric field in MQW. Subsequently, we discuss the recent progress in improving the IQE of green LED in detail. These strategies can be divided into two categories. Some of these methods were proposed to enhance crystal quality of InGaN/GaN MQW with high In composition and low density of defects by modifying the growth conditions. Other methods focused on increasing electron-hole wave function overlap by eliminating the polarization effect.

scholarly journals Using InGaN/GaN Multiple Quantum well Green light-Emitting Diodes as a Promising Replacement of Conventional light Sources

2019 ◽  
Vol 9 (1) ◽  
pp. 5205-5209
Keyword(s):  
Multiple Quantum Well ◽  
Three Dimensional ◽  
Green Light ◽  
Light Sources ◽  
Multiple Quantum ◽  
Internal Electric Field ◽  
Light Emitting ◽  
Green Led ◽  
P Type ◽  
The Impact

In this particular paper we increase a graded indium composition p type InGaN (p InGaN) conduction level to supplant the p type AlGaN electron blocking level & a p GaN level to update the mild yield intensity of a GaN based green light transmitting diode (LED). The indium structure of the p InGaN coating reduced from 10.4 % to zero % across the development heading. A tale configuration is proposed for n-electrode with openings to be connected in Thin-GaN light-transmitting diodes (LEDs). The impact of the n-electrode with gaps on the thermal and electrical qualities of a Thin-GaN LED chip is researched utilizing a three-dimensional numerical simulation The IQE of green LED is restricted by the deformities and the internal electric field in MQW. Thusly, we talk about the ongoing advancement in improving the IQE of green LED in detail. These techniques can be partitioned into two classes. A portion of these techniques were proposed to upgrade precious stone nature of InGaN/GaN MQW with high. In composition and low thickness of deformities by adjusting the development conditions. Different strategies concentrated on expanding electron−hole wave function cover by dispensing with the polarization impact.

Low-Temperature Operation of Green, Blue and UV InGaN/GaN Multiple-Quantum-Well Light-Emitting Diodes

2003 ◽  
Vol 764 ◽  
Author(s):  
X. A. Cao ◽  
S. F. LeBoeuf ◽  
J. L. Garrett ◽  
A. Ebong ◽  
L. B. Rowland ◽  
...  
Keyword(s):  
Quantum Well ◽  
Light Emitting Diodes ◽  
Multiple Quantum Well ◽  
Light Output ◽  
Localized States ◽  
Multiple Quantum ◽  
Nonradiative Recombination ◽  
Light Emitting ◽  
Temperature Range ◽  
Green Leds

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.

scholarly journals Improved Performance of GaN-Based Light-Emitting Diodes Grown on Si (111) Substrates with NH3 Growth Interruption

Micromachines ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 399
Author(s):  
Sang-Jo Kim ◽  
Semi Oh ◽  
Kwang-Jae Lee ◽  
Sohyeon Kim ◽  
Kyoung-Kook Kim
Keyword(s):  
Buffer Layer ◽  
Light Emitting Diodes ◽  
Defect Density ◽  
Strain Relaxation ◽  
Multiple Quantum Well ◽  
Light Output ◽  
Multiple Quantum ◽  
Light Emitting ◽  
Growth Interruption ◽  
Aln Buffer

We demonstrate the highly efficient, GaN-based, multiple-quantum-well light-emitting diodes (LEDs) grown on Si (111) substrates embedded with the AlN buffer layer using NH3 growth interruption. Analysis of the materials by the X-ray diffraction omega scan and transmission electron microscopy revealed a remarkable improvement in the crystalline quality of the GaN layer with the AlN buffer layer using NH3 growth interruption. This improvement originated from the decreased dislocation densities and coalescence-related defects of the GaN layer that arose from the increased Al migration time. The photoluminescence peak positions and Raman spectra indicate that the internal tensile strain of the GaN layer is effectively relaxed without generating cracks. The LEDs embedded with an AlN buffer layer using NH3 growth interruption at 300 mA exhibited 40.9% higher light output power than that of the reference LED embedded with the AlN buffer layer without NH3 growth interruption. These high performances are attributed to an increased radiative recombination rate owing to the low defect density and strain relaxation in the GaN epilayer.

High-Bright InGaN Multiple-Quantum-Well Blue Light-Emitting Diodes on Si (111) Using AlN/GaN Multilayers with a Thin AlN/AlGaN Buffer Layer

2003 ◽  
Vol 42 (Part 2, No. 3A) ◽  
pp. L226-L228 ◽  
Author(s):  
Baijun Zhang ◽  
Takashi Egawa ◽  
Hiroyasu Ishikawa ◽  
Yang Liu ◽  
Takashi Jimbo
Keyword(s):  
Quantum Well ◽  
Buffer Layer ◽  
Blue Light ◽  
Light Emitting Diodes ◽  
Multiple Quantum Well ◽  
Multiple Quantum ◽  
Light Emitting ◽  
Algan Buffer

Electroabsorption by Stark effect on room‐temperature excitons in GaAs/GaAlAs multiple quantum well structures

1983 ◽  
Vol 42 (10) ◽  
pp. 864-866 ◽  
Author(s):  
D. S. Chemla ◽  
T. C. Damen ◽  
D. A. B. Miller ◽  
A. C. Gossard ◽  
W. Wiegmann
Keyword(s):  
Quantum Well ◽  
Room Temperature ◽  
Stark Effect ◽  
Multiple Quantum Well ◽  
Multiple Quantum ◽  
Quantum Well Structures
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