scholarly journals Improving Emission Uniformity of InGaN/GaN-Based Vertical LEDs by Using Reflective ITO/Ag n-Contact

Electronics ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 975
Author(s):  
Woong-Sun Yum ◽  
Ji-Hyun Koo ◽  
Dae-Hee Lee ◽  
Young-Hoon Kim ◽  
Young-Kyu Jeong ◽  
...  
Keyword(s):  
Output Power ◽  
Light Emitting Diodes ◽  
Reference Sample ◽  
Light Output ◽  
Light Output Power ◽  
Forward Voltage ◽  
Light Emitting ◽  
Wall Plug Efficiency ◽  
Chip Size ◽  
Reference Samples

We investigated the effect of Ti/Al and ITO/Ag n-type contacts on the emission uniformity and light output of different chip-size vertical-geometry light-emitting diodes (VLEDs) for vehicle headlamp application. The forward voltage of the Ti/Al-based reference VLEDs decreased from 3.38 to 3.20 V at 1500 mA with increasing chip size from (1280 × 1000 µm2) to (1700 × 1700 µm2), whereas that of the ITO/Ag-based samples changed from 3.37 to 3.15 V. Regardless of chip size, the ITO/Ag-based samples revealed higher light output power than the reference samples. For example, the ITO/Ag-based samples (chip size of 1700 × 1700 µm2) exhibited 3.4% higher light output power at 1500 mA than the reference samples. The ITO/Ag samples underwent less degradation in the Wall-plug efficiency (WPE) than the reference sample. For instance, the ITO/Ag-based samples (1700 × 1700 µm2) gave 4.8% higher WPE at 1500 mA than the reference samples. The ITO/Ag-based samples illustrated more uniform emission than the Ti/Al-based sample. Both the reference and ITO/Ag-based samples underwent no degradation when operated at 1500 mA for 1000 h.

Improved Light Output Power of GaN-Based Light-Emitting Diodes Using Double Photonic Quasi-Crystal Patterns

2009 ◽  
Vol 30 (11) ◽  
pp. 1152-1154 ◽  
Author(s):  
Hung-Wen Huang ◽  
Chung-Hsiang Lin ◽  
Zhi-Kai Huang ◽  
Kang-Yuan Lee ◽  
Chang-Chin Yu ◽  
...  
Keyword(s):  
Output Power ◽  
Light Emitting Diodes ◽  
Light Output ◽  
Light Output Power ◽  
Light Emitting

Electroluminescence Properties of Eu-doped GaN-based Light-emitting Diodes Grown by Organometallic Vapor Phase Epitaxy

2011 ◽  
Vol 1342 ◽  
Author(s):  
Atsushi Nishikawa ◽  
Naoki Furukawa ◽  
Dong-gun Lee ◽  
Kosuke Kawabata ◽  
Takanori Matsuno ◽  
...  
Keyword(s):  
Layer Thickness ◽  
Output Power ◽  
Active Layer ◽  
Vapor Phase ◽  
Light Emitting Diodes ◽  
Light Output ◽  
Active Layer Thickness ◽  
Organometallic Vapor Phase Epitaxy ◽  
Light Output Power ◽  
Light Emitting

ABSTRACTWe investigated the electroluminescence (EL) properties of Eu-doped GaN-based light-emitting diodes (LEDs) grown by organometallic vapor phase epitaxy (OMVPE). The thickness of the active layer was varied to increase the light output power. With increasing the active layer thickness, the light output power monotonically increased. The maximum light output power of 50 μW was obtained for an active layer thickness of 900 nm with an injected current of 20 mA, which is the highest value ever reported. The corresponding external quantum efficiency was 0.12%. The applied voltage for the LED operation also increased with the active layer thickness due to an increase in the resistance of the LED. Therefore, in terms of power efficiency, the optimized active layer thickness was around 600 nm. These results indicate that the optimization of the LED structure would effectively improve the luminescence properties.

Ni-assisted Fabrication of GaN Based Surface Nano-textured Light Emitting Diodes for Improved Light Output Power

2015 ◽  
Vol 15 (4) ◽  
pp. 454-461 ◽  
Author(s):  
Mumta Hena Mustary ◽  
Beo Deul Ryu ◽  
Min Han ◽  
Jong Han Yang ◽  
Volodymyr V. Lysak ◽  
...  
Keyword(s):  
Output Power ◽  
Light Emitting Diodes ◽  
Light Output ◽  
Light Output Power ◽  
Light Emitting

Improved Light Output Power of GaN-based Light Emitting Diodes using Double Photonic Quasi-Crystal Patterned

2009 ◽  
Author(s):  
J. K. Huang ◽  
H. W. Huang ◽  
C. H. Lin ◽  
K. Y. Lee ◽  
C. C. Yu ◽  
...  
Keyword(s):  
Output Power ◽  
Light Emitting Diodes ◽  
Light Output ◽  
Light Output Power ◽  
Light Emitting
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