Browsing by Author "Huang, Shih-Yung"

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AlGaInP Red LEDs with Hollow Hemispherical Polystyrene Arrays
(2018-01-17)
Cheng, Wen-Ching
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Huang, Shih-Yung
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Chen, Yi-Jiun
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Wang, Chia-Sheng
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Lin, Hoang Yan
A hollow hemispherical polystyrene (HHPS) was fabricated to reduce total internal reflection in AlGaInP-based LEDs. At an injection current of 350 mA, the external quantum efficiencies of LED-I, LED-II, LED-III, and LED-IV are 20.92%, 24.65%, 27.28%, and 33.77% and the wall-plug efficiencies are 17.11%, 20%, 22.5%, and 27.33%, respectively. The enhanced performance is attributed to the light output power enhancement through the surface roughness, microlens-liked PS hemisphere, and scatter-liked HHPS array. In this paper, the rigorous coupled wave analysis (RCWA) numerical method was also conducted to demonstrate the HHPS array effectively enlarge the effective light cone.
Fabrication and characterization of InGaN-based green resonant-cavity LEDs using hydrogen ion-implantation techniques
(2007)
Huang, Shih-Yung
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Horng, Ray-Hua
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Kuo, Hao-Chung
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Wuu, Dong-Sing
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光電工程學系
The InGaN-based green resonant-cavity light-emitting diodes (RCLEDs) have been fabricated using hydrogen ion-implantation and laser liftoff techniques. The RCLEDs structure consisted of an InGaN/GaN multiple-quantum-well active layer between the top (5 pairs) and bottom (7.5 pairs) dielectric TiO2/SiO2 distributed Bragg reflectors with optical reflectance of 85% and 99.9%, respectively. The insulation layers of the RCLEDs with and without H+ implantation were formed by the hydrogen ion-implantation layers of 1x10(14) ions/cm(2) concentration and SiO2 film, respectively. The corresponding forward turn-on voltage at 0.6 kA/cm(2) dc current density injection were about similar to 4.58 V and similar to 4.55 V for the RCLEDs with and without H+ implantation. The light output intensity of the RCLEDs with H+ implantation is higher by a factor of 1.4 as compared to that of the similar structure without H+ implantation at a current density of 0.6 kA/cm(2). The directionality of RCLEDs with H+ implantation is superior to that of RCLEDs without H+ implantation. (c) 2007 The Electrochemical Society.
High-Performance InGaN-Based Green Resonant-Cavity Light-Emitting Diodes for Plastic Optical Fiber Applications
(2009-09-15)
Huang, Shih-Yung
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Horng, Ray-Hua
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Shi, Jin-Wei
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Kuo, Hao-Chung
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Wuu, Dong-Sing
High-performance InGaN-based green resonant-cavity light-emitting diodes (RCLEDs) with a plating Cu substrate for plastic optical fiber communication applications are reported. Good stability of emission wavelength was obtained at 0.016 nm/mA. The RCLEDs presents low temperature dependence, showing only a 3% drop in light output power as the temperature increasing from 25 to 85 degrees C. The superior performance can be attributed to the decreased dynamic series resistance and the enhanced thermal dissipation of the heat sink substrate.
Reduction of Defects in AlGaN Grown on Nanoscale-Patterned Sapphire Substrates by Hydride Vapor Phase Epitaxy
(2017-06-01)
Tasi, Chi-Tsung
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Wang, Wei-Kai
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Tsai, Tsung-Yen
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Huang, Shih-Yung
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Horng, Ray-Hua
In this study, a 3-m-thick AlGaN film with an Al mole fraction of 10% was grown on a nanoscale-patterned sapphire substrate (NPSS) using hydride vapor phase epitaxy (HVPE). The growth mechanism, crystallization, and surface morphology of the epilayers were examined using X-ray diffraction, transmission electron microscopy (TEM), and scanning electron microscopy at various times in the growth process. The screw threading dislocation (TD) density of AlGaN-on-NPSS can improve to 1-2 x 10(9) cm(-2), which is significantly lower than that of the sample grown on a conventional planar sapphire substrate (7 x 10(9) cm(-2)). TEM analysis indicated that these TDs do not subsequently propagate to the surface of the overgrown AlGaN layer, but bend or change directions in the region above the voids within the side faces of the patterned substrates, possibly because of the internal stress-relaxed morphologies of the AlGaN film. Hence, the laterally overgrown AlGaN films were obtained by HVPE, which can serve as a template for the growth of ultraviolet III-nitride optoelectronic devices.
Structural and Stress Properties of A1GaN Epilayers Grown on A1N-Nanopatterned Sapphire Templates by Hydride Vapor Phase Epitaxy
(2018-09-01)
Tasi, Chi-Tsung
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Wang, Wei-Kai
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Ou, Sin-Liang
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Huang, Shih-Yung
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Horng, Ray-Hua
In this paper, we report the epitaxial growth and material characteristics of AlGaN (Al mole fraction of 10%) on an AlN/nanopatterned sapphire substrate (NPSS) template by hydride vapor phase epitaxy (HYPE). The crystalline quality, surface morphology, microstructure, and stress state of the AlGaN/AlN/NPSS epilayers were investigated using X-ray diffraction (XRD), atomic force microscopy (AFM), and transmission electron microscopy (TEM). The results indicate that the crystal quality of the A1GaN film could be improved when grown on the A1N/NPSS template. The screw threading dislocation (TD) density was reduced to 1.4 x 10(9) cm(-2) for the AlGaN epilayer grown on the A1N/NPSS template, which was lower than that of the sample grown on a flat c-plane sapphire substrate (6.3 x 10(9) cm(-2)). As examined by XRD measurements, the biaxial tensile stress of the AlGaN film was significantly reduced from 1,187 MPa (on A1N/NPSS) to 38.41 MPa (on flat c-plane sapphire). In particular, an increase of the Al content in the overgrown AlGaN layer was confirmed by the TEM observation. This could be due to the relaxation of the in-plane stress through the AlGaN and AlN/NPSS template interface.
Tissue transglutaminase is involved in mechanical load-induced osteogenic differentiation of human ligamentum flavum cells
(2016)
Chao, Yuan-Hung
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Huang, Shih-Yung
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Yang, Ruei-Cheng
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Sun, Jui-Sheng
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友訊交大聯合研發中心
Mechanical load-induced osteogenic differentiation might be the key cellular event in the calcification and ossification of ligamentum flavum. The aim of this study was to investigate the influence of tissue transglutaminase (TGM2) on mechanical load-induced osteogenesis of ligamentum flavum cells. Human ligamentum flavum cells were obtained from 12 patients undergoing lumbar spine surgery. Osteogenic phenotypes of ligamentum flavum cells, such as alkaline phosphatase (ALP), Alizarin red-S stain, and gene expression of osteogenic makers were evaluated following the administration of mechanical load and BMP-2 treatment. The expression of TGM2 was evaluated by real-time PCR, Western blotting, and enzyme-linked immunosorbent assay (ELISA) analysis. Our results showed that mechanical load in combination with BMP-2 enhanced calcium deposition and ALP activity. Mechanical load significantly increased ALP and OC gene expression on day 3, whereas BMP-2 significantly increased ALP, OPN, and Runx2 on day 7. Mechanical load significantly induced TGM2 gene expression and enzyme activity in human ligamentum flavum cells. Exogenous TGM2 increased ALP and OC gene expression; while, inhibited TG activity significantly attenuated mechanical load-induced and TGM2-induced ALP activity. In summary, mechanical load-induced TGM2 expression and enzyme activity is involved in the progression of the calcification of ligamentum flavum.