Enhanced light output of InGaN/GaN blue light emitting diodes with Ag nano-particles embedded in nano-needle layer

The GaN-based flip-chip white light-emitting diodes (FCWLEDs) with diffused ZnO nanorod reflector and with ZnO nanorod antireflection layer were fabricated. The ZnO nanorod array grown using an aqueous solution method was combined with Al metal to form the diffused ZnO nanorod reflector. It could avoid the blue light emitted out from the Mg-doped GaN layer of the FCWLEDs, which caused more blue light emitted out from the sapphire substrate to pump the phosphor. Moreover, the ZnO nanorod array was utilized as the antireflection layer of the FCWLEDs to reduce the total reflection loss. The light output power and the phosphor conversion efficiency of the FCWLEDs with diffused nanorod reflector and 250 nm long ZnO nanorod antireflection layer were improved from 21.15 mW to 23.90 mW and from 77.6% to 80.1% in comparison with the FCWLEDs with diffused nanorod reflector and without ZnO nanorod antireflection layer, respectively.

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Decreasing CCT deviation of white light emitting diodes by employing SiO2 nanoparticles

Bulletin of Electrical Engineering and Informatics ◽

10.11591/eei.v10i3.3041 ◽

2021 ◽

Vol 10 (3) ◽

pp. 1316-1324

Author(s):

My Hanh Nguyen Thi ◽

Phung Ton That

Keyword(s):

White Light ◽

Light Emitting Diodes ◽

Internal Quantum Efficiency ◽

Light Output ◽

Sio2 Nanoparticles ◽

Nano Particles ◽

Light Extraction Efficiency ◽

Light Emitting ◽

White Leds ◽

White Light Emitting Diodes

In this research, the SiO2 nano-particles (NPs) usage in enhancing optical performances of InGaN/GaN-based white light-emitting diodes (WLEDs) with remote phosphor structure. The research subject shows better lighting capacity than the white LEDs devices without the space between the layers. The adjustment in development process resulted in enhancements of internal quantum efficiency (IQE) and light extraction efficiency (LEE) that lead to 13.5% luminous efficacy improvement. From the experiments, it can be concluded that the LEE is affected by the trapped light and enhancing the light output with SiO2 scattering properties reduce the amount of trapped light. These results confirm that SiO2 nano-particles is effective in enhancing the optical performance of WLEDs and can be considered for production of higher quality devices.

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Performance of InGaN/GaN Light Emitting Diodes with n-GaN Layer Embedded with SiO2 Nano-Particles

Applied Sciences ◽

10.3390/app8091574 ◽

2018 ◽

Vol 8 (9) ◽

pp. 1574 ◽

Cited By ~ 3

Author(s):

Hong-Seo Yom ◽

Jin-Kyu Yang ◽

Alexander Polyakov ◽

In-Hwan Lee

Keyword(s):

High Performance ◽

Light Emitting Diodes ◽

Internal Quantum Efficiency ◽

Light Output ◽

Front Surface ◽

Nano Particles ◽

Light Extraction Efficiency ◽

Light Emitting ◽

Dry Etch ◽

Air Void

We demonstrate high-performance InGaN/GaN blue light emitting diodes (LEDs) embedded with an air-void layer produced by a dry-etch of nano-pillars in an n-GaN layer grown on patterned sapphire substrate (PSS), filling the space between nano-pillars with SiO2 nano-particles (NPs) and subsequent epitaxial overgrowth. The structure exhibits enhanced output power compared to similarly grown reference conventional LED without the air-void layer. This change in growth procedure contributes to the increase of internal quantum efficiency (IQE) and light extraction efficiency (LEE) resulting in a 13.5% increase of light output. LEE is 2 times more affected than IQE in the modified structure. Simulation demonstrates that the main effect causing the LEE changes is due to the emitted light being confined within the upper space above the air-void layer and thus enhancing the light scattering by the SiO2 NPs and preferential light via front surface.

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Ag/SiO2 nanoparticle-based plasmonic enhancement of light output in nanohole-patterned InGaN/GaN blue light-emitting diodes

Japanese Journal of Applied Physics ◽

10.7567/jjap.56.100305 ◽

2017 ◽

Vol 56 (10) ◽

pp. 100305

Author(s):

Jin-Hyeon Yun ◽

Kyu Cheol Kim ◽

Yeon Tae Yu ◽

Jin Kyu Yang ◽

Alexander Y. Polyakov ◽

...

Keyword(s):

Blue Light ◽

Light Emitting Diodes ◽

Light Output ◽

Plasmonic Enhancement ◽

Light Emitting ◽

Sio2 Nanoparticle

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Determination of current-crowding effects on loss of light-output power in InGaN/GaN blue-light-emitting diodes

Journal of the Korean Physical Society ◽

10.3938/jkps.67.346 ◽

2015 ◽

Vol 67 (2) ◽

pp. 346-349 ◽

Cited By ~ 1

Author(s):

Hye-Jung Yu ◽

Yanqun Dong ◽

Tae-Soo Kim ◽

Jin-Gyu Lee ◽

Nan-Cho Oh ◽

...

Keyword(s):

Output Power ◽

Blue Light ◽

Light Emitting Diodes ◽

Light Output ◽

Current Crowding ◽

Light Output Power ◽

Light Emitting ◽

Crowding Effects

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Lattice Constant Effect of Photonic Crystals on the Light Output of Blue Light-Emitting Diodes

IEEE Photonics Technology Letters ◽

10.1109/lpt.2008.927893 ◽

2008 ◽

Vol 20 (17) ◽

pp. 1455-1457 ◽

Cited By ~ 14

Author(s):

Keunjoo Kim ◽

Jaeho Choi ◽

Jong Bae Park ◽

Sang Cheol Jeon ◽

Jin Soo Kim ◽

...

Keyword(s):

Photonic Crystals ◽

Blue Light ◽

Lattice Constant ◽

Light Emitting Diodes ◽

Light Output ◽

Light Emitting

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

MRS Proceedings ◽

10.1557/proc-764-c5.5 ◽

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.

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Blue light emitting diodes cripple Helicobacter pylori by targeting its virulence factors

Minerva Gastroenterologica e Dietologica ◽

10.23736/s1121-421x.19.02593-5 ◽

2019 ◽

Vol 65 (3) ◽

Author(s):

Homa Darmani ◽

Ehda Am Smadi ◽

Sereen Mb Bataineh

Keyword(s):

Helicobacter Pylori ◽

Blue Light ◽

Virulence Factors ◽

Light Emitting Diodes ◽

Light Emitting

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

Micromachines ◽

10.3390/mi12040399 ◽

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.

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