Browsing by Author "Chou, Hsiu-Mei"

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Current Spreading Improvement in GaN-Based Light-Emitting Diode Grown on Nano-Rod GaN Template
(2012-04-01)
Kuo, Cheng-Huang
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Chang, Li-Chuan
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Chou, Hsiu-Mei
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照明與能源光電研究所
;
Institute of Lighting and Energy Photonics
In this letter, we demonstrate GaN-based light-emitting diodes (LEDs) with high-quality heavily-Si-doped n-GaN prepared on a nano-rod GaN (NR-GaN) template. With 20-mA current injection, it was found that light output power (LOP) can be enhanced 29.0%, as compared to the conventional LED. Enhancement of the LOP can be attributed to the improvement of the current spreading and the increase of light extraction efficiency by using the heavily-Si-doped n-GaN prepared on the NR-GaN template.
High-efficiency InGaN-based LEDs grown on patterned sapphire substrates using nanoimprinting technology
(2013-05-01)
Lee, Yeeu-Chang
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Yeh, Shiang-Chih
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Chou, Yen-Yu
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Tsai, Pei-Jung
;
Pan, Jui-Wen
This study employed roller imprint lithography and dry etching to fabricate patterned sapphire substrates (PSSs) of convex-shape with features of various heights. A soft polymer, polydimethylsiloxane (PDMS), was used as a mold to duplicate the pattern of a hard silicon template. The imprinted material was spin deposited onto a PDMS mold and transferred to the sapphire substrate using roller imprinting equipment. Inductive coupled plasma (ICP) etching was then used to fabricate the PSS. After epitaxial growth and chip processing, the current-voltage characteristics and light output of various LEDs were measured. The results demonstrate that the PSS process did not detract from the electrical properties of the LEDs; in fact, the output power of the proposed PSS LEDs was 25-30% greater than that of conventional LEDs. Simulation results show that PSS LEDs with structures of various heights would enhance optical efficiency in a manner similar to that demonstrated in these experiments. (C) 2013 Elsevier B.V. All rights reserved.
Regrowth of High Quality Heavily Si-Doped nGaN Utilizing Nano-Rod GaN Template
(2011)
Kuo, Cheng-Huang
;
Chang, Li-Chuan
;
Chou, Hsiu-Mei
;
照明與能源光電研究所
;
Institute of Lighting and Energy Photonics
In this study, heavily Si-doped n-type GaN (n-GaN) epitaxial layers with and without nanorod GaN (NR GaN) template were grown by metal organic chemical vapor deposition (MOCVD) system. It was found that we could achieve high-qulaity heavily Si-doped n-GaN layers by using the NR GaN template. It was also found that we can reduce etching pits density in n-GaN (1.5E19 cm(-3)) epitaxial layer by a factor of 2.82 using the NR GaN template, as compared to the conventional sapphire substrate. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3617533] All rights reserved.