Enhancement of light extraction from light emitting diodes

Zhmakin, Alexander I.

doi:10.1016/j.physrep.2010.11.001

Cited by 281 publications

(186 citation statements)

References 692 publications

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“…As we know, the low LEE of LEDs was mainly due to the effects of total internal reflection (TIR) and Fresnel reflection [29], especially the TIR. Under the influence of TIR, the LEE of LEDs can be defined as…”

Section: The Light Extraction Of Planar Ledsmentioning

confidence: 99%

Using Three-Component Hierarchical Structures to Improve the Light Extraction From White Leds Based on Red-Green-Blue Color Mixing Method

Li¹,

Li²,

Kong³

et al. 2017

PIER C

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Abstract-In this work, we present a three-component hierarchical structure to simultaneously improve the red, green, and blue (RGB) light extraction efficiency (LEE) of white light-emitting diodes (LEDs) based on color mixing method. With the help of 3D finite-difference time-domain (FDTD) simulations, the effects of the embedded photonic crystals (PhCs) the normal surface PhCs and the nano-rods on the enhancement of RGB light extraction were investigated. The results were compared with those of the conventional planar LEDs and the normal surface PhCs LEDs over the whole visible spectrum. Results from the simulations demonstrated that the maximum LEE for the hierarchical structures LEDs gave 112%, 327%, and 284% RGB LEE enhancement, respectively, compared to that of the conventional planar LEDs, and achieved 104%, 191%, and 187% RGB LEE enhancement compared to that of LEDs with normal surface PhCs. The emission characteristics of the hierarchical structures LEDs were also revealed in detail by FDTD simulations. The results shown in this paper would do a favor for the design and fabrication of high efficiency LEDs.

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Section: The Light Extraction Of Planar Ledsmentioning

confidence: 99%

Using Three-Component Hierarchical Structures to Improve the Light Extraction From White Leds Based on Red-Green-Blue Color Mixing Method

Li¹,

Li²,

Kong³

et al. 2017

PIER C

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“…The rapid advances in the hetero-epitaxy of the group-III nitrides (Fernández-Garrido et al (2008); Kemper et al (2011); Suihkonen et al (2008)) have facilitated the production of new devices, including blue and UV LEDs and lasers, high temperature and high power electronics, visible-blind photodetectors and field-emitter structures (Hirayama (2005); Hirayama et al (2010); Tschumak et al (2010); Xie et al (2007); Zhu et al (2007)). There has been recent interest in the Al x In 1−x−y Ga y N quaternary alloys due to potential application in UV LEDs and UV-blue laser diodes (LDs) once they present high brightness, high quantum efficiency, high flexibility, long-lifetime, and low power consumption (Fu et al (2011);Hirayama (2005); Kim et al (2003); Knauer et al (2008); Liu et al (2011);Park et al (2008); Zhmakin (2011);Zhu et al (2007)). The availability of the quaternary alloy offers an extra degree of freedom which allows the independent control of the band gap and lattice constant.…”

Section: Introductionmentioning

confidence: 99%

Application of Quaternary AlInGaN- Based Alloys for Light Emission Devices

Rodrigues¹,

Sipahi²,

Scolfaro³

et al. 2011

Optoelectronics - Materials and Techniques

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“…When these microstructures are introduced into the devices, the near-field radiative electromagnetic properties of the devices are changed, which can lead to an improvement in the light emission efficiency. Because of the differences between the refractive indices of the semiconductor layers in the LED chip, the photons produced by radiative recombination in the relatively high index layer suffer from total internal reflection (TIR) [1,2]. The evanescent waves and guided modes that result from the TIR cannot escape from the layers, which results in a reduction in the light emission efficiency.…”

mentioning

confidence: 99%

“…These methods can be divided into two categories [2]: those that change the propagation paths of the radiated photons through the introduction of microstructures, and those that use the microstructures to change the spontaneous emission properties of the active region of the LED chip. A method based on the surface plasmons (SPs) of the microstructures can improve the light emission efficiency attributed to the enhancement of the spontaneous emission.…”

mentioning

confidence: 99%

The application of the microstructured metallic grating to light emission extraction

Gou

Xuan

2013

Chin. Sci. Bull.

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Microstructured metallic gratings can be used to enhance the light emission efficiency of LEDs, and the spectral radiation properties of the LEDs vary with the different metallic materials used, leading to variation of the light emission enhancement at the same wavelength for different metallic grating materials. In this paper, the finite difference time domain (FDTD) method has been used to investigate the light emission extraction enhancement of LEDs in which gratings with different metallic materials have been applied. Through analysis of the permittivity of the metals and the quality factors of the surface plasmons (SPs), we concluded that the larger the plasma frequency obtained for the metallic interband transition, then the more suitable the metals are for light emission extraction of photons with relatively short wavelengths. This is because of the abundance of free electrons in the metals with large plasma frequencies. We also found that the wavelength-dependent trends of the extraction enhancement resulting from the scattering mechanism for different metallic materials are similar to each other. For SP-induced enhancement, either the enhancement peak position or the peak value changes significantly with the different metals.

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Enhancement of light extraction from light emitting diodes

Cited by 281 publications

References 692 publications

Using Three-Component Hierarchical Structures to Improve the Light Extraction From White Leds Based on Red-Green-Blue Color Mixing Method

Using Three-Component Hierarchical Structures to Improve the Light Extraction From White Leds Based on Red-Green-Blue Color Mixing Method

Application of Quaternary AlInGaN- Based Alloys for Light Emission Devices

The application of the microstructured metallic grating to light emission extraction

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