Browsing by Author "Lee, K. Y."

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Efficiency Improvement of GaN-Based LEDs With a SiO(2) Nanorod Array and a Patterned Sapphire Substrate
(2010-06-01)
Huang, H. W.
;
Huang, J. K.
;
Lin, C. H.
;
Lee, K. Y.
;
Hsu, H. W.
The enhancement of light extraction from GaN-based light-emitting diodes (LEDs) with a patterned sapphire substrate (PSS) and a SiO(2) 12-fold photonic quasi-crystal (PQC) structure using nanoimprint lithography is presented. At a driving current of 20 mA on transistor-outline-can package, the light output powers of LED with a PSS and LED with a PSS and a SiO(2) PQC structure are enhanced by 35% and 48%, compared with the conventional LED. In addition, the higher output power of the LED with a PSS and a SiO(2) PQC structure is due to better reflectance on PSS and higher epitaxial quality on an n-GaN using a SiO(2) 12-fold PQC structure pattern. These results provide promising potential to increase output powers of commercial light-emitting devices.
Efficiency Improvement of GaN-Based LEDs With a SiO2 Nanorod Array and a Patterned Sapphire Substrate
(2010-06-01)
Huang, H. W.
;
Huang, J. K.
;
Lin, C. H.
;
Lee, K. Y.
;
Hsu, H. W.
The enhancement of light extraction from GaN-based light-emitting diodes (LEDs) with a patterned sapphire substrate (PSS) and a SiO2 12-fold photonic quasi-crystal (PQC) structure using nanoimprint lithography is presented. At a driving current of 20 mA on transistor-outline-can package, the light output powers of LED with a PSS and LED with a PSS and a SiO2 PQC structure are enhanced by 35% and 48%, compared with the conventional LED. In addition, the higher output power of the LED with a PSS and a SiO2 PQC structure is due to better reflectance on PSS and higher epitaxial quality on an n-GaN using a SiO2 12-fold PQC structure pattern. These results provide promising potential to increase output powers of commercial light-emitting devices.
Enhanced light output power of GaN-based vertical-injection light-emitting diodes with a 12-fold photonic quasi-crystal by nano-imprint lithography
(2009-08-12)
Huang, H. W.
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Lin, C. H.
;
Lee, K. Y.
;
Yu, C. C.
;
Huang, J. K.
GaN-based thin-film vertical-injection light-emitting diodes (VLEDs) with a 12-fold photonic quasi-crystal (PQC) by nano-imprint lithography (NIL) are fabricated and presented. At a driving current of 20 mA and with a chip size of 350 mu m x 350 mu m, the light output power of our thin-film LED with a 12-fold PQC structure reaches 41 mW. This result is an enhancement of 78% when compared with the output power of a VLED without a PQC structure. In addition, the corresponding light radiation pattern shows a narrower beam shape due to the strong guided light extraction effect by the formed PQC structure in the vertical direction.
Enhancement of light output power of GaN-based light-emitting diodes using a SiO(2) nano-scale structure on a p-GaN surface
(2010-06-01)
Huang, H. W.
;
Lai, F. I.
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Huang, J. K.
;
Lin, C. H.
;
Lee, K. Y.
GaN (gallium nitride)-based light-emitting diodes (LEDs) with a nano-scale SiO(2) structure between a transparent indium-tin oxide (ITO) layer and p-GaN were fabricated. The forward voltage at 20 mA for a GaN-based LED with a SiO(2) nano-scale structure was slightly higher than that of a conventional GaN-based LED because the total area of the p-type metal contact between the transparent ITO layer and p-GaN was smaller. However, the light output power for the GaN-based LED with a nano-scale structured SiO(2) at 20 mA was 24% higher than that for a conventional GaN-based LED structure. This increase in the light output power is mostly attributed to the scattering of light from the SiO(2) photonic quasi-crystal (PQC) layer.
Enhancement of light output power of GaN-based light-emitting diodes using a SiO2 nano-scale structure on a p-GaN surface
(2010-06-01)
Huang, H. W.
;
Lai, F. I.
;
Huang, J. K.
;
Lin, C. H.
;
Lee, K. Y.
GaN (gallium nitride)-based light-emitting diodes (LEDs) with a nano-scale SiO2 structure between a transparent indium-tin oxide (ITO) layer and p-GaN were fabricated. The forward voltage at 20 mA for a GaN-based LED with a SiO2 nano-scale structure was slightly higher than that of a conventional GaN-based LED because the total area of the p-type metal contact between the transparent ITO layer and p-GaN was smaller. However, the light output power for the GaN-based LED with a nano-scale structured SiO2 at 20 mA was 24% higher than that for a conventional GaN-based LED structure. This increase in the light output power is mostly attributed to the scattering of light from the SiO2 photonic quasi-crystal (PQC) layer.
Investigation of GaN-based light emitting diodes with nano-hole patterned sapphire substrate (NHPSS) by nano-imprint lithography
(2009-08-25)
Huang, H. W.
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Lin, C. H.
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Huang, J. K.
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Lee, K. Y.
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Lin, C. F.
In this paper, gallium-nitride (GaN)-based light-emitting diodes (LEDs) with nano-hole patterned sapphire (NHPSS) by nano-imprint lithography are fabricated and investigated. At an injection current of 20mA, the LED with NHPSS increased the light output power of the InGaN/GaN multiple quantum well LEDs by a factor of 1.33, and the wall-plug efficiency is 30% higher at 20mA indicating that the LED with NHPSS had larger light extraction efficiency. In addition, by examining the radiation patterns, the LED with NHPSS shows stronger light extraction with a wider view angle. These results offer promising potential to enhance the light output powers of commercial light-emitting devices using the technique of nano-imprint lithography. (C) 2009 Elsevier B.V. All rights reserved.
Investigation of GaN-based light-emitting diodes using double photonic crystal patterns
(2011-02-01)
Huang, H. W.
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Lai, Fang-I
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Kuo, S. Y.
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Huang, J. K.
;
Lee, K. Y.
GaN-based LEDs with photonic crystal (PhC) patterns on an n- and a p-GaN layer by nano-imprint lithography (NIL) are fabricated and investigated. At a driving current of 20 mA on Transistor Outline (TO)-can package, the light output power of the GaN-based LED with PhC patterns on an n- and a p-GaN layer is enhanced by a factor of 1.30, and the wall-plug efficiency is increased by 24%. In addition, the higher output power of the LED with PhC patterns on the n- and p-GaN layer is due to better crystal quality on n-GaN and higher scattering effect on p-GaN surface using PhC pattern structure. (C) 2010 Elsevier Ltd. All rights reserved.
Investigation of GaN-based vertical-injection light-emitting diodes with GaN nano-cone structure by ICP etching
(2008-07-25)
Huang, H. W.
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Lin, C. H.
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Yu, C. C.
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Lee, K. Y.
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Lee, B. D.
The GaN-based thin-film vertical-injection LEDs (VLEDs) with GaN nano-cone structures are fabricated and presented. Under the process conditions of fixed Cl(2)/Ar now rate of 10/25sccm and ICP/bias power of 200/200W, the GaN nano-cone structures are self-assembly formed with variable density of 1.5 x 10(7) to 1.4 x 10(1) cm(-2) and variable depth of 0.56-1.34 mu m when varying the ICP chamber pressure. At a driving current of 350mA and with chip size of 1 mm x 1 mm, the light output power of our thin-film LED with a specific GaN nano-cone structure reaches 224 mW which is enhanced by 160% when compared with the output power of conventional VLED. In addition, the corresponding light radiation pattern Shows Much higher light intensity Clue to the strong light scattering effect by the formed nano-cone Structure. (C) 2008 Elsevier B.V. All rights reserved.
Light Extraction Efficiency Enhancement of GaN-Based Light Emitting Diodes on n-GaN Layer Using a SiO(2) Photonic Quasi-Crystal Overgrowth
(2010-10-01)
Huang, H. W.
;
Lee, K. Y.
;
Huang, J. K.
;
Lin, C. H.
;
Lin, C. F.
In this paper, GaN-based LEDs with a SiO(2) photonic quasi-crystal (PQC) pattern on an n-GaN layer by nano-imprint lithography (NIL) are fabricated and investigated. At a driving current of 20 mA on Transistor Outline (TO)-can package, the better light output power of LED III (d = 1.2 mu m) was enhanced by a factor of 1.20. After 1000 h life test (55 degrees C/50 mA) condition, Normalized output power of LED with a SiO(2) PQC pattern (LED III (d = 1.2 mu m)) on an n-GaN layer only decreased by 5%. This results offer promising potential to enhance the light output power of commercial light-emitting devices using the technique of nano-imprint lithography.
Light-Output-Power Enhancement of GaN-Based Light-Emitting Diodes on an n-GaN Layer Using a SiO(2) Photonic Quasi-Crystal Overgrowth
(2010-06-01)
Huang, H. W.
;
Huang, J. K.
;
Lee, K. Y.
;
Lin, C. F.
;
Kuo, H. C.
GaN-based LEDs with a SiO(2) oxide PQC pattern on an n-GaN layer by nanoimprint lithography are fabricated and investigated. At a driving current of 20 mA on a Transistor-Outline-can package, the light output power of LED III (d = 1.2 mu m) was enhanced by a factor of 1.20. The internal-quantum-efficiency result offers promising potential to enhance the light output power of commercial light-emitting devices with a SiO(2) oxide PQC structure on an n-GaN layer.
Light-Output-Power Enhancement of GaN-Based Light-Emitting Diodes on an n-GaN Layer Using a SiO2 Photonic Quasi-Crystal Overgrowth
(2010-06-01)
Huang, H. W.
;
Huang, J. K.
;
Lee, K. Y.
;
Lin, C. F.
;
Kuo, H. C.
GaN-based LEDs with a SiO2 oxide PQC pattern on an n-GaN layer by nanoimprint lithography are fabricated and investigated. At a driving current of 20 mA on a Transistor-Outline-can package, the light output power of LED III (d = 1.2 mu m) was enhanced by a factor of 1.20. The internal-quantum-efficiency result offers promising potential to enhance the light output power of commercial light-emitting devices with a SiO2 oxide PQC structure on an n-GaN layer.