Light emitting enhancement and angle-resolved property of surface textured GaN-based vertical LED

Liu, Zhe; Zhu, Chuanrui; Wang, Yujin; Shen, Yan; Yang, Hang; Gu, Changzhi; Li, Junjie; Liu, Baoli; Xu, Xiangang

doi:10.1007/s12596-015-0304-3

Cited by 8 publications

(2 citation statements)

References 23 publications

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“…To this end, the photon escaped from the gallium nitride (GaN) sidewall can be increased by reducing the TIR, thereby realizing the improvement of light extraction efficiency (LEE) and light efficiency [14][15][16]. Several advantageous approaches have been put forward to increase the LEE, such as patterned sapphire substrates [17][18][19], textured surfaces [19][20][21][22], SiO 2 MS/MP [9,23,24], composite transparent conductive layer [5,25], microlens array [26,27], and photon crystals [16,28,29]. Meanwhile, the LEE can be improved by roughening the bottom [30] or sidewalls of the LED.…”

Section: Introductionmentioning

confidence: 99%

Light Extraction Enhancement of InGaN Based Micro Light-Emitting Diodes with Concave-Convex Circular Composite Structure Sidewall

Tan

Zhou

et al. 2019

Applied Sciences

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We demonstrate that the concave-convex circular composite structure sidewall prepared by inductively coupled plasma (ICP) etching is an effective approach to increase the light efficiency without deteriorating the electrical characteristics for micro light-emitting diodes (LEDs). The saturated light output power of the device using the concave-convex circular composite structure sidewalls with a radius of 2 μm is 39.75 mW, an improvement of 7.2% compared with that of the device using flat sidewalls. The enhanced light output characteristics are primarily attributed to the increased photon emitting due by decreasing the total internal reflection without losing the active region area.

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Section: Introductionmentioning

confidence: 99%

Light Extraction Enhancement of InGaN Based Micro Light-Emitting Diodes with Concave-Convex Circular Composite Structure Sidewall

Tan

Zhou

et al. 2019

Applied Sciences

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“…The LEE performance can be improved by reducing the total internal reflection (TIR) and Fresnel reflection and increasing photons to escape from the active region of LEDs. 8,9 Over the past years, numerous approaches, e.g., pattern sapphire substrates, 10,11 antireflection layers, 12,13 textured surfaces, 14,15 textured sidewalls, [16][17][18] microhole arrays, [19][20][21][22] and backside reflectors 23,24 have been reported to enhance the LEE properties of GaN-based LEDs.…”

mentioning

confidence: 99%

Study of a GaN-Based Light-Emitting Diode with a Specific Hybrid Structure

Chen

Niu

Liu³

et al. 2021

ECS J. Solid State Sci. Technol.

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A specific hybrid structure, including 45° sidewalls, a shallower (0.25 μm in depth) microhole array, and a 3-D like backside reflector, is used to fabricate GaN-based light-emitting diodes (LEDs). The 3-D like backside reflector is formed by the deposition of 100 nm-diameter SiO2 nanospheres (NSs) and an Al layer on the sapphire substrate. Based on the use of 45° sidewall and microhole array, the reduced total internal reflection (TIR) and Fresnel reflection and the increased scattering probability and the opportunity of photons to find escape cones can be expected. In addition, the use of 3-D like backside reflector can effectively reflect scatter, and redirect the downward photons emitted from multiple quantum well (MQW) region into arbitrary directions. Thus, the light extraction performance can be substantially improved. In experiment, under an injection current of 400 mA, the studied Device D with this hybrid structure shows enhancements of 47.4%, 47.7%, 33.1%, and 47.8% in light output power (LOP), external quantum efficiency (EQE), luminous flux, and wall-plug efficiency (WPE), respectively, as compared to a conventional LED. Moreover, the related electrical properties are not degraded for the studied Device D. Therefore, this hybrid structure shows a promise for high-performance GaN-based LED applications.

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Self‐Assembled Nanowrinkle‐Network‐Structured Transparent Conductive Zinc Oxide for High‐Efficiency Inorganic Light‐Emitting Diodes

Lee

2021

Adv Materials Inter

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A ZnO nanowrinkle network (NWN) film is applied as a transparent conductive electrode (TCE) to improve the light extraction efficiency of inorganic light‐emitting diodes (LEDs). The NWN structures in sol–gel‐derived ZnO films are spontaneously formed by the evaporation of the solvent during prebaking to achieve the gelation of the sol–gel ZnO film. Despite the NWN structure, the optical transmittance of the NWN‐ZnO film prebaked at 130 °C is maintained at ≈92% with respect to that of unmodified glass. However, the optical transmittance of the NWN‐ZnO film prebaked at 150 °C is significantly decreased because of the increase in nanowrinkle density. As a result, the electroluminescence intensity of LEDs having the NWN‐ZnO TCEs increases significantly for the samples prebaked at temperatures up to 130 °C but decreases slightly in those treated at 150 °C. In addition, LEDs having the NWN‐ZnO film show enhanced spectral distribution over wide angles, which is important for lighting applications. On the basis of these results, the spontaneously assembled NWN‐ZnO films formed by the sol–gel method show potential for the low‐cost production of inorganic LEDs having high light extraction efficiencies.

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Light emitting enhancement and angle-resolved property of surface textured GaN-based vertical LED

Cited by 8 publications

References 23 publications

Light Extraction Enhancement of InGaN Based Micro Light-Emitting Diodes with Concave-Convex Circular Composite Structure Sidewall

Light Extraction Enhancement of InGaN Based Micro Light-Emitting Diodes with Concave-Convex Circular Composite Structure Sidewall

Study of a GaN-Based Light-Emitting Diode with a Specific Hybrid Structure

Self‐Assembled Nanowrinkle‐Network‐Structured Transparent Conductive Zinc Oxide for High‐Efficiency Inorganic Light‐Emitting Diodes

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