Long-wavelength shift of ZnSSe metal-semiconductor-metal light-emitting diodes with high injection currents

2000 ◽  
Author(s):  
Yan-Kuin Su ◽  
Wen Ray Chen ◽  
Shoou-Jinn Chang ◽  
Fuh-Shyang Juang ◽  
W. H. Lan ◽  
...  
Keyword(s):  
Light Emitting Diodes ◽  
Wavelength Shift ◽  
Light Emitting ◽  
Long Wavelength ◽  
High Injection ◽  
Metal Semiconductor Metal ◽  
Injection Currents

The red shift of ZnSSe metal-semiconductor-metal light emitting diodes with high injection currents

2000 ◽  
Vol 47 (7) ◽  
pp. 1330-1333 ◽  
Author(s):  
Y.K. Su ◽  
W.R. Chen ◽  
S.J. Chang ◽  
F.S. Juang ◽  
W.H. Lan ◽  
...  
Keyword(s):  
Light Emitting Diodes ◽  
Red Shift ◽  
Light Emitting ◽  
High Injection ◽  
Metal Semiconductor Metal ◽  
Injection Currents

scholarly journals Demonstration of epitaxial growth of strain-relaxed GaN films on graphene/SiC substrates for long wavelength light-emitting diodes

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Ye Yu ◽  
Tao Wang ◽  
Xiufang Chen ◽  
Lidong Zhang ◽  
Yang Wang ◽  
...  
Keyword(s):  
Epitaxial Growth ◽  
Light Emitting Diodes ◽  
Nitrogen Plasma ◽  
Biaxial Stress ◽  
Organic Chemical ◽  
Graphene Surface ◽  
Light Emitting ◽  
Long Wavelength ◽  
Pre Treatment ◽  
Wavelength Light

AbstractStrain modulation is crucial for heteroepitaxy such as GaN on foreign substrates. Here, the epitaxy of strain-relaxed GaN films on graphene/SiC substrates by metal-organic chemical vapor deposition is demonstrated. Graphene was directly prepared on SiC substrates by thermal decomposition. Its pre-treatment with nitrogen-plasma can introduce C–N dangling bonds, which provides nucleation sites for subsequent epitaxial growth. The scanning transmission electron microscopy measurements confirm that part of graphene surface was etched by nitrogen-plasma. We study the growth behavior on different areas of graphene surface after pre-treatment, and propose a growth model to explain the epitaxial growth mechanism of GaN films on graphene. Significantly, graphene is found to be effective to reduce the biaxial stress in GaN films and the strain relaxation improves indium-atom incorporation in InGaN/GaN multiple quantum wells (MQWs) active region, which results in the obvious red-shift of light-emitting wavelength of InGaN/GaN MQWs. This work opens up a new way for the fabrication of GaN-based long wavelength light-emitting diodes.

Approaches Towards the Ultimate Luminous Output Power of Light-Emitting Diodes: Bottlenecks and Remedies

2015 ◽  
Author(s):  
Xiaokun Zhang ◽  
Xiao-Dong Xiang ◽  
Yong Xiang
Keyword(s):  
Output Power ◽  
Light Emitting Diodes ◽  
Thermal Runaway ◽  
Efficiency Droop ◽  
Injection Current ◽  
Light Emitting ◽  
Excessive Heat ◽  
High Injection ◽  
Current Densities ◽  
The Cost

Although light-emitting diodes (LEDs) hold great promises for high-efficiency lighting applications, the cost per lumen still poses a challenge for LEDs to fast penetrate into the markets. Increasing the output power per LED chip reduces the number of chips required for a specific luminous flux, thus reducing the cost of LED luminaires. However, it is well known that the luminous output power of LEDs (Pout) cannot be enhanced simply by increasing the injection current density (Jinj) due to efficiency droop. Extensive efforts have been made towards avoiding efficiency droop at high injection current densities (e.g., Jinj > 50 A/cm2). Gardner et al. reported a double-heterostructure LED with an external quantum efficiency (EQE) of 40% at 200 A/cm2. Xie et al. introduced an electron-blocking layer into the LED devices and the EQE peak occurred at 900 A/cm2 approximately. Nevertheless, the EQE is always lower than 100%, excessive heat will accumulate in LEDs at high current densities and increase the junction temperatures, which will damage the device and limit its luminous output power and lifetime. In this paper, the recombination mechanism in the LED active area is analyzed and an analytic relationship between Pout and Jinj is proposed. The calculated results show that the best Pout currently achieved is far lower than its potential value. The temperature dependence of the Pout-Jinj relationship is also calculated and the thermal state of LEDs at high injection current densities predicted. The results demonstrate that LED luminaires with thermal management based on conventional fin-shaped heat sinks suffer from thermal runaway due to excessive heat accumulation before reaching their ultimate output power. The gap between the existing and predicted Pout is mainly due to thermal runaway of LED devices at high injection current densities, instead of efficiency droop. Therefore, the short-term solution of LED luminous output power enhancement should be better cooling of LED modules, such as jet/spray cooling, heat pipe cooling, or 3D embedded two-phase cooling. Long-term solutions continue to focus on reducing the efficiency droop with improved LED device structures and advanced materials.

scholarly journals Saga of efficiency degradation at high injection in InGaN light emitting diodes

2014 ◽  
Vol 38 ◽  
pp. 269-313 ◽  
Author(s):  
Vitaliy AVRUTIN ◽  
Shopan A. HAFIZ ◽  
Fan ZHANG ◽  
Ümit ÖZGÜR ◽  
Enrico BELLOTTI ◽  
...  
Keyword(s):  
Light Emitting Diodes ◽  
Light Emitting ◽  
High Injection

InGaN light-emitting diodes: Efficiency-limiting processes at high injection

2013 ◽  
Vol 31 (5) ◽  
pp. 050809 ◽  
Author(s):  
Vitaliy Avrutin ◽  
Shopan din Ahmad Hafiz ◽  
Fan Zhang ◽  
Ümit Özgür ◽  
Hadis Morkoç ◽  
...  
Keyword(s):  
Light Emitting Diodes ◽  
Light Emitting ◽  
High Injection

Long-wavelength light-emitting diodes (λ=3.4–3.9 µm) based on InAsSb/InAs heterostructures grown by vapor-phase epitaxy

2000 ◽  
Vol 34 (12) ◽  
pp. 1402-1405 ◽  
Author(s):  
N. V. Zotova ◽  
S. S. Kizhaev ◽  
S. S. Molchanov ◽  
T. B. Popova ◽  
Yu. P. Yakovlev
Keyword(s):  
Vapor Phase ◽  
Light Emitting Diodes ◽  
Vapor Phase Epitaxy ◽  
Light Emitting ◽  
Long Wavelength ◽  
Wavelength Light

S6-G4: High injection and efficiency droop in GaInN light-emitting diodes

2014 ◽  
Author(s):  
Guan-Bo Lin ◽  
David S. Meyaard ◽  
E. Fred Schubert ◽  
Jaehee Cho ◽  
Jong Kyu Kim ◽  
...  
Keyword(s):  
Light Emitting Diodes ◽  
Efficiency Droop ◽  
Light Emitting ◽  
High Injection
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