Browsing by Author "Chen, Yu An"

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Efficiency Improvement of Near-Ultraviolet Nitride-Based Light-Emitting-Diode Prepared on GaN Nano-Rod Arrays by Metalorganic Chemical Vapor Deposition
(2014-03-01)
Kuo, Cheng Huang
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Chen, Yu An
;
Wu, Ji Pu
;
Chang, Li Chuan
;
照明與能源光電研究所
Near-ultraviolet nitride-based light-emitting diodes (LEDs) were prepared on GaN nanorod arrays (NRAs). Transmission electron microscopy results show that the NRAs partially block threading dislocation propagation from the GaN template. Compared with conventional LEDS, the output power of the prepared LED using GaN NRAs with an injection current of 20 mA was enhanced by a factor of 1.67.
GaN-Based Light-Emitting-Diode With a p-InGaN Layer
(2014-03-01)
Chen, P. H.
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Kuo, Cheng-Huang
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Lai, W. C.
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Chen, Yu An
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Chang, L. C.
GaN-based LEDs with a p-InGaN layer was proposed and fabricated. By inserting the 50-nm-thick p-In0.01Ga0.99N layer, it was found that we could reduce the 20 mA forward voltage from 3.34 to 2.99 V. It was found the inserted p-InGaN layer could also reduce the efficiency droop from 36.7% to 23.8%.
Low operation voltage of GaN-based LEDs with Al-doped ZnO upper contact directly on p-type GaN without insert layer
(2015-07-01)
Chen, P. H.
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Chen, Yu An
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Chang, L. C.
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Lai, W. C.
;
Kuo, Cheng Huang
Al-doped ZnO (AZO) film was evaporated on double-side polished sapphire, p-GaN layers, n(+)-InGaN-GaN short-period superlattice (SPS) structures, and GaN-based light-emitting diodes (LEDs) by e-beam. The AZO film on the p-GaN layer after thermal annealing exhibited an extremely high transparency (98% at 450 nm) and a small specific contact resistance of 2.19 x 10(-2) Omega cm(2), which was almost the same as that of as-deposited AZO on n(+)-SPS structure. With 20 mA injection current, the forward voltages were 3.30 and 3.27 V, whereas the output powers were 4.32 and 4.07 mW for the LED with AZO on insert n(+)-SPS upper contact and the LED with AZO on p-GaN upper contact (without insert layer), respectively. The small specific contact resistance and low operation voltage of LED with AZO on p-GaN upper contact was achieved by rapid thermal annealing (RTA) process. (C) 2015 Elsevier Ltd. All rights reserved.
Nitride-Based Blue Light-Emitting Diodes Grown With InN/GaN Matrix Quantum Wells
(2014-04-01)
Kuo, Cheng-Huang
;
Fu, Yi Keng
;
Chang, L. C.
;
Chen, Yu An
;
照明與能源光電研究所
Nitride-based light-emitting diodes (LEDs) grown with a structure of InN/GaN matrix quantum-wells (QWs) using metal-organic chemical vapor deposition are fabricated and characterized. The InN/GaN matrix QWs can significantly enhance the formation of phase-separated In-rich regions. Under an injection current of 500 A/cm(2), the LED output power can be enhanced by 26%, and the efficiency droop can be improved as compared with a conventional LED. These improvements could be attributed to the strong localization effect to remove carriers from the confining potential and capture these carriers at nonradiative centers in the active layer.