Enhancement of InGaN-Based Vertical LED With Concavely Patterned Surface Using Patterned Sapphire Substrate

Lee, Jae‐Hoon; Oh, Jae Eung; Choi, Seok-Boem; Kim, Yong-Chun; Cho, Hyun-Ick; Lee, Jung‐Hee

doi:10.1109/lpt.2007.915648

Cited by 44 publications

(22 citation statements)

References 9 publications

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“…Especially, controlling the texture formation in LED is important because thickness of GaN decreases with increasing an etching time. 9 Therefore, detailed understanding of the LEE phenomena associated with texture size, thickness of GaN layer, and that's relation in LED structure is still required for higher device performance.…”

confidence: 99%

Experimental study of light output power for vertical GaN-based light-emitting diodes with various textured surface and thickness of GaN layer

et al. 2012

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The light output power (LOP) of vertical-type GaN-based light emitting diodes (LED) with surface roughness (texture) can be changed by texture size, density, and thickness of GaN film or by the combined effects of texture formation and thickness of GaN film. We have investigated these changes experimentally and note that the enhancement of the LOP by a factor of 2.4 can be improved with optimum texturing parameters as compared to that without texturing. In addition, the LOP of GaN-based LEDs under the same texture density increase slightly as thickness of GaN film decreases. Base on these results, we have evidently demonstrated that the enhancement factors of LOP are related to the correlation between texture size (density) and thickness of GaN film.

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confidence: 99%

Experimental study of light output power for vertical GaN-based light-emitting diodes with various textured surface and thickness of GaN layer

et al. 2012

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“…일반적인 LED에서 방출되는 빛은 생성된 빛의 극히 일부분에 지나지 않으며 대부분의 빛은 LED 외부로 방 출되지 못하고 내부에 갇히게 되어 LED의 광 추출 효율은 낮을 수 밖에 없다 [3] . 적 요철구조를 만드는 텍스처링(texturing) 기술 [4] , 나노 형상 의 주기적 패턴인 포토닉 크리스탈(photonic crystal) 기술 [5] , 사파이어(sapphire) 기판의 표면에 주기적인 요철을 가공한 사파이어 가공기판 (patterned sapphire substrate) 기술 [6] , 매 우 얇은 금속 막을 이용한 표면 플라즈몬 (surface plasmon) 기술 [7] …”

Section: 서 론 발광 다이오드(Led)는 기존의 여러 광원들을 대체할 차세 대 광원으로써 조명 자동차 의료unclassified

A Study of the Upper Layer for Improvement of the Extraction Efficiency in LED

최철현¹,

이동진²,

임해동³

et al. 2011

Korean Journal of Optics and Photonics

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In this paper, we improved the light extraction efficiency by considering an additional upper layer on the top surface of a conventional LED. We simulated the LED's light emission as functions of the thickness and the refractive index of the upper layer, and analyzed how the condition improved the light efficiency. When the refractive index's range was from 1.05 to 1.40, the LED emission increased. For that case, the emission also increased as the thickness increased. We experimentally showed that the light extraction efficiency was improved about 22% by forming the upper layer on the top surface of an LED using material with refractive index 1.30 at 589.3 nm. It is expected that forming the upper layer on an LED can easily improve the extraction efficiency.

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“…Regardless of the advantages of light-emitting diodes (LEDs), including high energy efficiency, long lifetime, vivid colors, high reliability, environmental protection, and safety, the external quantum efficiency (EQE, η ext ) is still an important issue that must be addressed to meet practical needs [1,2]. The EQE of an LED can be expressed as the product of the current injection efficiency (CIE, η inj ), internal quantum efficiency (IQE, η int ), and light extraction efficiency (LEE, η extr ) [3,4].…”

Section: Introductionmentioning

confidence: 99%

Improvement of Light Extraction Efficiency of LED Packages Using an Enhanced Encapsulant Design

Choi

Park

Moon

2014

Journal of the Optical Society of Korea

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We optimized the design of the flat encapsulant of a light-emitting diode (LED) package to obtain higher light output power (LOP), both by experiment and simulation using three-dimensional ray-tracing software. In the experiment, the refractive index of the encapsulant was varied (1.41 and 1.53). In addition, double-layer structures with these refractive indices (1.41/1.53) were investigated by varying the shape of the interface between the two among flat, concave, and convex. The experiments showed that the LOP of the double-layer encapsulant with convex interface increased by 13.4% compared to the single-layer encapsulant with a refractive index 1.41, which was explained by the increase of the light extraction efficiency (LEE) in connection with the increase of the critical angle (θ c ) and the decrease of the Fresnel reflection.

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Enhancement of InGaN-Based Vertical LED With Concavely Patterned Surface Using Patterned Sapphire Substrate

Cited by 44 publications

References 9 publications

Experimental study of light output power for vertical GaN-based light-emitting diodes with various textured surface and thickness of GaN layer

Experimental study of light output power for vertical GaN-based light-emitting diodes with various textured surface and thickness of GaN layer

A Study of the Upper Layer for Improvement of the Extraction Efficiency in LED

Improvement of Light Extraction Efficiency of LED Packages Using an Enhanced Encapsulant Design

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