Improved light extraction of GaN-based light-emitting diodes by ITO patterning with optimization design

Wang, Pei; Cao, Bin; Wei, Wei; Gan, Zhiyin; Liu, Sheng

doi:10.1016/j.sse.2009.10.005

Cited by 18 publications

(6 citation statements)

References 16 publications

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“…Finally, I would like to discuss the light output properties of the LEDs with different pillar sizes. According to the report by Wang et al, 32) it is found that different sizes of pillar patterns give rise to different light scattering effect. In Sample 1, due to the smaller gap size between the pillar patterns, the photons have greater opportunities to enter the pillar structure and then escape via scattering (or diffraction) out of the semiconductor, compared to Sample 2.…”

Section: Resultsmentioning

confidence: 98%

The Light Extraction Efficiency of p-GaN Patterned InGaN/GaN Light-Emitting Diodes Fabricated by Size-Controllable Nanosphere Lithography

Sim

Lee

Yang

et al. 2011

Jpn. J. Appl. Phys.

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The authors present a light extraction improvement at a low operation voltage from p-GaN patterned InGaN/GaN light-emitting diodes (LEDs) fabricated using size-controllable nanosphere lithography and subsequent inductively coupled plasma etching. A 300-nm polystyrene (PS) nanosphere array was used as an etching mask in order to produce ordered pillar patterns on the p-GaN layer, during which the top and bottom size of the pillars were tailored to optimize the electrical and optical properties by varying the diameter of the PS nanosphere masks. Three LEDs, without patterns and with pillar patterns of 210 nm and 240 nm diameter, were compared with each other, in which the LED with 240 nm diameter pillar patterns showed the highest output power (32.6% higher than that of the LEDs without patterns) in both its electroluminescence and photoluminescence measurements.

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Section: Resultsmentioning

confidence: 98%

The Light Extraction Efficiency of p-GaN Patterned InGaN/GaN Light-Emitting Diodes Fabricated by Size-Controllable Nanosphere Lithography

Sim

Lee

Yang

et al. 2011

Jpn. J. Appl. Phys.

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“…After that, the SiO 2 array on the bottom of the substrate can be prepared by standard photolithography and wet-etching. The triangle-lattice in the photolithography mask is composed of hollow circles with a diameter of 3 μ m and a periodicity of 6 μ m. These parameters of triangle-lattice are limited by the resolution of standard ultraviolet lithography due to the Fresnel diffraction effect [ 15 ]. After 5 min wet-etching using buffered oxide etchant (BOE), the SiO 2 cone array can be obtained.…”

Section: Methodsmentioning

confidence: 99%

Light-Output Enhancement of GaN-Based Light-Emitting Diodes with Three-Dimensional Backside Reflectors Patterned by Microscale Cone Array

Huang

Wang

2014

The Scientific World Journal

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Three-dimensional (3D) backside reflector, compared with flat reflectors, can improve the probability of finding the escape cone for reflecting lights and thus enhance the light-extraction efficiency (LEE) for GaN-based light-emitting diode (LED) chips. A triangle-lattice of microscale SiO2 cone array followed by a 16-pair Ti3O5/SiO2 distributed Bragg reflector (16-DBR) was proposed to be attached on the backside of sapphire substrate, and the light-output enhancement was demonstrated by numerical simulation and experiments. The LED chips with flat reflectors or 3D reflectors were simulated using Monte Carlo ray tracing method. It is shown that the LEE increases as the reflectivity of backside reflector increases, and the light-output can be significantly improved by 3D reflectors compared to flat counterparts. It can also be observed that the LEE decreases as the refractive index of the cone material increases. The 3D 16-DBR patterned by microscale SiO2 cone array benefits large enhancement of LEE. This microscale pattern was prepared by standard photolithography and wet-etching technique. Measurement results show that the 3D 16-DBR can provide 12.1% enhancement of wall-plug efficiency, which is consistent with the simulated value of 11.73% for the enhancement of LEE.

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“…The results showed that the luminous flux, luminous efficiency and radiant power of LED decrease greatly with the cycling time at firstly and keep a constant at last during the cycling process of 40-150°C, and approximately reduce 60%. The rapid thermal cycling had an [8][9][10][11][12][13]. Therefore, the reason of the luminous flux and luminous efficiency decreased is found out according to above analysis.…”

Section: 3 Experimental Setup and Testingmentioning

confidence: 99%

Rapid thermal cycling by eddy current inducted heating on optical property and thermostability of high power LED

Chen

Guo

Liu

et al. 2012

2012 13th International Conference on Electronic Packaging Technology &Amp; High Density Packaging

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The effect of rapid thermal cycling by eddy current inducted heating on optical property and thermostability of high power light emitting diode (LED) is investigated in the present study. With the application of high-frequency power device, the specimen that was being operated life test in the experiment was rapidly heated and cooled based on a control system that employs a fuzzy logic algorithm. The high and low temperature distribution in LED chip was simulated by finite element modeling (FEM) . The optical properties of single LED was tested and analyzed by integrating sphere. It was found that rapid thermal cycling has an evident influence on luminous flux and luminous efficiency and radiant power. The results showed that the color purity of LED was also descended, but the correlated color temperature (CCT) was risen. The results indicate that this approach to rapid thermal cycling by eddy current is feasible to investigate optical property and thermostability of high power LED, so it can also effectively verifY the reliability of LED devices.

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Improved light extraction of GaN-based light-emitting diodes by ITO patterning with optimization design

Cited by 18 publications

References 16 publications

The Light Extraction Efficiency of p-GaN Patterned InGaN/GaN Light-Emitting Diodes Fabricated by Size-Controllable Nanosphere Lithography

The Light Extraction Efficiency of p-GaN Patterned InGaN/GaN Light-Emitting Diodes Fabricated by Size-Controllable Nanosphere Lithography

Light-Output Enhancement of GaN-Based Light-Emitting Diodes with Three-Dimensional Backside Reflectors Patterned by Microscale Cone Array

Rapid thermal cycling by eddy current inducted heating on optical property and thermostability of high power LED

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