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10:45 - 11:00
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Manuscript ID. 0214
Paper No. 2022-SAT-S0703-O001
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| Tien-Chiu Chen
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Efficiency Improvement of AlGaN-Based Ultraviolet Light-Emitting Diodes by Superlattice Contact Layer and Nano-Patterned Sapphire Substrates
Tien-Chiu Chen, Hung-Chang Hsieh, Tsung-Sheng Kao, Chia-Yen Huang, National Yang Ming Chiao Tung University (Taiwan)
We fabricated UVC light-emitting diodes (LEDs) with different p-contact layers and sapphire substrates and investigated their effects on external quantum efficiency (EQE). At I = 350 mA, the EQE of the LEDs on the flat sapphire substrate (FSS) with a p-type superlattice (p-SL) contact layer is 3.9%, while that with a p-GaN contact layer is only 2.4%. If the FSS is replaced with nano-patterned sapphire substrate (NPSS), the EQE of the LEDs with the p-SL structure was further improved to 4.4%. We also analyzed the LEDs far-field intensity to explore the root of improvement of NPSS and p-SL on EQE.
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11:00 - 11:15
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Manuscript ID. 0234
Paper No. 2022-SAT-S0703-O002
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| Heish Hung Chang
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High-quality AlGaN epitaxy on strain-engineered AlN for high efficiency UVC light-emitting diodes
Heish Hung Chang, Chen Tien Chiu, Kao Tsung Sheng, Wu Jhih Sheng, Huang Chia Yen, Yang Ming National Chiao Tung University (Taiwan)
AlGaN-based UVC light-emitting diodes (LEDs) were fabricated on engineered AlN template with a superior quality of AlGaN. The controllability of AlN strain status was resulted from the vacancy-dislocation interaction in Si-doped AlN. With a high-quality and sufficiently thick AlGaN injection layer, a low forward voltage (Vf = 5.7 volt) at I = 1.35 A UVC LED was demonstrated. The low forward voltage yielded a decent wall-plug efficiency (WPE=3.5%) under a high current injection.
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11:15 - 11:30
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Manuscript ID. 0134
Paper No. 2022-SAT-S0703-O003
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| Yin-Xuan Zheng
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Development of Direct-type Auto-Dimming Backlight Modul Conforming to Area Uniformity Standards
Guu-huann Liu, Yin-Xuan Zheng, Epoch Chemtronics Corp. (Taiwan)
Through intelligent local dimming, the LED current is adjusted to improve the area uniformity of the direct-type backlight module. It has energy-saving effect, and with the mass production process design, the direct-type backlight module has a more competitive advantage in the market.
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11:30 - 11:45
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Manuscript ID. 0817
Paper No. 2022-SAT-S0703-O004
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| Yi-Xuan Wang
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High efficiency micro-scale UVC light-emitting diodes with surrounding porous-AlGaN structures
Yi-Xuan Wang, National Chung Hsing University (Taiwan)
The micro-scale AlGaN-based UVC light-emitting diodes with the porous-AlGaN structures were demonstrated through the lateral electrochemically (EC) etching process. The aperture emission region was observed in the EC-LED that was defined by the lateral EC process. EC-treated AlGaN layer has high oxygen content that could be formed as the AlGaOx layer. EL peak wavelength had a blueshift phenomenon in the EC-LED (279.0nm) compared to the ST-LED (280.3nm) for the 50×50 um2 in size that was caused by partial strain released in the AlGaN active layers. High light scattering process, electric insulated property, and polarized emission were observed in EC-treated LED.
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11:45 - 12:00
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Manuscript ID. 0366
Paper No. 2022-SAT-S0703-O005
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| Tsung-Yin Tsai
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Investigation of alloy disorder effects in conventional III-V and III-nitride semiconductors by localization landscape theory and the Schrodinger equation
Tsung-Yin Tsai, National Taiwan University (Taiwan), University of California, Santa Barbara (USA); Kai Shek Qwah, University of California, Santa Barbara (USA); claude weisbuch, Institut Polytechnique de Paris (France), University of California, Santa Barbara (USA); Yuh-Renn Wu, National Taiwan University (Taiwan); James Speck, University of California, Santa Barbara (USA)
In this work, the effects of alloy disorder in III-nitride and conventional III-V semiconductors were investigated by localization landscape (LL) theory and the Schrodinger equation. Landscape potential maps show alloy potential fluctuation in conventional III-Arsenide semiconductors is much flatter than III-nitrides. The standard deviations of conduction and valence bands and landscape potentials show there are big differences in alloy potential fluctuation between InxGa1-xN and InxGa1-xAs due to the differences in bandgap variation with composition and carrier effective masses.
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