Improved light output power of InGaN/GaN MQW LEDs by lower temperature p-GaN rough surface

Liu, C. H.; Chuang, Ricky W.; Chang, Shoou‐Jinn; Su, Yan–Kuin; Wu, Long; Lin, Chien‐Chung

doi:10.1016/j.mseb.2004.05.003

Cited by 65 publications

(24 citation statements)

References 22 publications

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“…The nano-roughened surface allows the photons emitted from the active regions to escape from the LEDs, accordingly, increases the LEE of LED devices. This mechanism for the improvement of light output power in our experiment agrees well with the previously reported [9,11,12]. It is necessary to point out that light output power of sample D is a little lower than sample C. We suspect that the lower output power of sample D is caused by the degradation of crystalline quality in p-GaN layer, which has been showed by XRD FWHMs above.…”

Section: Resultssupporting

confidence: 92%

“…This problem seriously hindered the realization of high external quantum efficiency (EQE) of LEDs. Some methods toward improving the LEE of LED devices have been proposed, mainly including photonic crystal (PC) [2,3], localized surface plasmons (LSPs) [4][5][6], patterned substrate [7] and surface roughening [8][9][10][11][12]. Specifically, surface roughening is widely accepted on account of its simple and efficient characteristics.…”

Section: Introductionmentioning

confidence: 99%

“…Another alternative is to control the growth conditions of epitaxial wafer, which is widely accepted in industrial application. Liu et al [11] obtained a rough surface of p-GaN layer through reducing the growth temperature of p-GaN. With the reduction of growth temperature in p-GaN layer, the crystal quality becomes poor, therefore, the LED devices have a high reverse leakage current (IR).…”

Section: Introductionmentioning

confidence: 99%

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Improvement of light extraction efficiency in InGaN/GaN-based light-emitting diodes with a nano-roughened p-GaN surface

Xiang-Jing

Zhang

et al. 2014

J Mater Sci: Mater Electron

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The following paper presents a study on the performance of InGaN/GaN-based light-emitting diodes (LEDs) with a nano-roughened p-GaN surface, which were grown by metal-organic chemical vapor deposition. This nano-roughened p-GaN surface was obtained by using nitrogen (N 2 ) as cyclopentadienyl magnesium (Cp 2 Mg) carrier gas during the growth of p-GaN layer. Research results show that the surface roughness of p-GaN layer is influenced by the injection flow of N 2 and the injection time of N 2 . Under the optimal process condition, the light output power of LED with a nano-roughened p-GaN surface is improved by 30.4 % compared with that of conventional LED with an injection current of 20 mA. Meanwhile, current-voltage curve shows that the electrical performance of this sample is similar to that of conventional LED. The improvement of light output power is mainly attributed to the higher light extraction efficiency when nano-roughened p-GaN surface is adopted.

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Section: Resultssupporting

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Improvement of light extraction efficiency in InGaN/GaN-based light-emitting diodes with a nano-roughened p-GaN surface

Xiang-Jing

Zhang

et al. 2014

J Mater Sci: Mater Electron

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“…Device reliability, lifetime, and degradation are affected by leakage current in high power operation. [1][2] Strong bias can damage an LED chip. Therefore, this study researches the leakage current behavior resulting from strong reverse-bias to operate LED chips.…”

Section: Introductionmentioning

confidence: 99%

Influence of strong reverse-bias on the leakage behavior of light-emitting diodes

Wang

Tseng

Chen

et al. 2007

2007 Conference on Lasers and Electro-Optics - Pacific Rim

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“…As well known, the large difference in the refractive index between the GaN(2.40) and air(1) caused a narrow escape cone for the light in GaN crystal. One most used method is roughness or texture on interfaces, such as the patterned sapphire substrate (PSS) recently [1], [2], [3], [4] , and the increasing efficiency of PSS LED is considered as a consequence of the light scattering by the PSS. Huang, etc developed the side wall shaping and truncated inverted pyramid (TIP) shaping technology to increase the external quantum efficiency (EQE) of GaN LED [5], [6] .…”

Section: Introductionmentioning

confidence: 99%

The effects of sapphire substrates processes to the LED efficiency

et al. 2007

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We investigate the relation between the thickness of sapphire substrates and the extraction efficiency of LED. The increasing about 5% was observed in the simulations and experiments when the sapphire thickness changed from 100um to 200um. But the output power increasing is inconspicuous when the thickness is more than 200um. The structure on bottom face of sapphire substrates can enhance the extraction efficiency of GaN-based LED, too. The difference of output power between the flip-chip LED with smooth bottom surface and the LED with roughness bottom surface is about 50%, where only a common sapphire grinding process is used. But for those LEDs grown on patterned sapphire substrate the difference is only about 10%. Another kind of periodic pattern on the bottom of sapphire is fabricated by the dry etch method, and the output of the back-etched LEDs is improved about 50% than a common case.

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Improved light output power of InGaN/GaN MQW LEDs by lower temperature p-GaN rough surface

Cited by 65 publications

References 22 publications

Improvement of light extraction efficiency in InGaN/GaN-based light-emitting diodes with a nano-roughened p-GaN surface

Improvement of light extraction efficiency in InGaN/GaN-based light-emitting diodes with a nano-roughened p-GaN surface

Influence of strong reverse-bias on the leakage behavior of light-emitting diodes

The effects of sapphire substrates processes to the LED efficiency

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