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

2018 ◽  
Vol 8 (9) ◽  
pp. 1574 ◽  
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.

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

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.

scholarly journals Nanostructural Effect of ZnO on Light Extraction Efficiency of Near-Ultraviolet Light-Emitting Diodes

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Young Jae Park ◽  
Hyounsuk Song ◽  
Kang Bok Ko ◽  
Beo Deul Ryu ◽  
Tran Viet Cuong ◽  
...  
Keyword(s):  
Ultraviolet Light ◽  
Indium Tin Oxide ◽  
Light Emitting Diodes ◽  
Light Output ◽  
Light Extraction Efficiency ◽  
Zno Nanostructures ◽  
Light Emitting ◽  
Near Ultraviolet ◽  
Output Efficiency ◽  
Ultraviolet Light Emitting Diodes

The effect of ZnO nanostructures on the light output power of 375 nm near-ultraviolet light-emitting diodes (NUV-LEDs) was investigated by comparing one-dimensional (1D) nanorods (NR-ZnO) with two-dimensional (2D) nanosheets (NS-ZnO). ZnO nanostructures were grown on a planar indium tin oxide (ITO) by solution based method at low temperature of 90°C without degradation of the forward voltage. At an injection current of 100 mA, the light output efficiency of NUV-LED with NR-ZnO was enhanced by around 30% compared to the conventional NUV-LEDs without ZnO nanostructures. This improvement is due to the formation of a surface texturing, resulting in a larger escape cone and a multiple scattering for the photons in the NUV-LED, whereas the light output efficiency of NUV-LED with NS-ZnO was lower than that of the conventional NUV-LEDs due to the internal reflection and light absorption in the defective sites of NS-ZnO.

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

2012 ◽  
Vol 20 (6) ◽  
pp. 6036 ◽  
Author(s):  
Lee-Woon Jang ◽  
Jin-Woo Ju ◽  
Dae-Woo Jeon ◽  
Jae-Woo Park ◽  
A. Y. Polyakov ◽  
...  
Keyword(s):  
Blue Light ◽  
Light Emitting Diodes ◽  
Light Output ◽  
Nano Particles ◽  
Light Emitting

scholarly journals Light Output Enhancement of InGaN/GaN Light-Emitting Diodes with Contrasting Indium Tin-Oxide Nanopatterned Structures

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Sang Hyun Jung ◽  
Keun Man Song ◽  
Young Su Choi ◽  
Hyeong-Ho Park ◽  
Hyun-Beom Shin ◽  
...  
Keyword(s):  
Circular Hole ◽  
Tin Oxide ◽  
Indium Tin Oxide ◽  
Inductively Coupled Plasma ◽  
Light Emitting Diodes ◽  
Hexagonal Lattice ◽  
Light Output ◽  
Light Extraction Efficiency ◽  
Output Intensity ◽  
Light Emitting

Various nanopatterns on the transparent conducting indium tin oxide (ITO) layer are investigated to enhance the light extraction efficiency of the InGaN/GaN light-emitting diodes (LEDs). Triangular, square, and circular nanohole patterns with the square and hexagonal lattices are fabricated on the ITO layer by an electron beam lithography and inductively coupled plasma dry etching processes. The circular hole pattern with a hexagonal geometry is found to be the most effective among the studied structures. Light output intensity measurements reveal that the circular hole nanopatterned ITO LEDs with a hexagonal lattice show up to 35.6% enhancement of output intensity compared to the sample without nanopatterns.

scholarly journals Deep Ultraviolet AlGaN-Based Light-Emitting Diodes with p-AlGaN/AlGaN Superlattice Hole Injection Structures

Processes ◽  
2021 ◽  
Vol 9 (10) ◽  
pp. 1727
Author(s):  
Tien-Yu Wang ◽  
Wei-Chih Lai ◽  
Syuan-Yu Sie ◽  
Sheng-Po Chang ◽  
Cheng-Huang Kuo ◽  
...  
Keyword(s):  
Light Emitting Diodes ◽  
Light Output ◽  
Light Extraction ◽  
Light Extraction Efficiency ◽  
Hole Injection ◽  
Carrier Injection ◽  
Light Emitting ◽  
Deep Ultraviolet ◽  
Reduced Light ◽  
A Current

The p-AlGaN/AlGaN superlattice (SL) hole injection structure was introduced into deep ultraviolet (DUV) light-emitting diodes (LEDs) to enhance their performances. The period thicknesses of the p-Al0.8Ga0.2N/Al0.48Ga0.52N SLs affected the performances of the DUV LEDs. The appropriate period thickness of the p-Al0.8Ga0.2N/Al0.48Ga0.52N SL may enhance the hole injection of DUV LEDs. Therefore, compared with the reference LEDs, the DUV LEDs with the 10-pair Al0.8Ga0.2N (1 nm)/Al0.48Ga0.52N (1 nm) SL presented forward voltage reduction of 0.23 V and light output power improvement of 15% at a current of 350 mA. Furthermore, the 10-pair Al0.8Ga0.2N (1 nm)/Al0.48Ga0.52N (1 nm) SL could slightly suppress the Auger recombination and current overflow of the DUV LEDs in a high-current operation region. In addition to improved carrier injection, the DUV LEDs with the p-Al0.8Ga0.2N/Al0.48Ga0.52N SL hole injection structure showed reduced light absorption at their emission wavelength compared with the reference LEDs. Therefore, the DUV LEDs with p-Al0.8Ga0.2N/Al0.48Ga0.52N SL may exhibit better light extraction efficiency than the reference LEDs. The enhancement of p-Al0.8Ga0.2N (1 nm)/Al0.48Ga0.52N (1 nm) SL may contribute to improvements in light extraction and hole injection.

The Light Extraction Efficiency Enhancement in Organic Light-Emitting Diodes with Substrate Modifications

2012 ◽  
Vol 605-607 ◽  
pp. 2031-2034
Author(s):  
Chong Wang ◽  
Jun Wang ◽  
Kai Yuan ◽  
Lei Yu
Keyword(s):  
Light Emitting Diodes ◽  
Extraction Efficiency ◽  
Internal Quantum Efficiency ◽  
Organic Thin Films ◽  
Organic Light Emitting Diodes ◽  
Light Extraction Efficiency ◽  
Light Emitting ◽  
Organic Layers ◽  
Organic Light ◽  
The Difference

The internal quantum efficiency of organic light-emitting diodes (OLEDs) can reach values near to 100%. Due to the difference among the refractive indices of the substrate, anode, organic thin films, and the air, two wave-guiding phenomena arise in the anode/organic layers and substrate of the OLEDs. In this paper, the substrate modifications are developed to simulate the optical luminous field for OLEDs. Monte Carlo method was used to investigate enhancement of the external extraction efficiency, which is related to the total reflection inside the device by changing the structure of the substrate.

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