Browsing by Author "Kuo, Cheng Huang"

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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.
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
;
Chang, L. C.
;
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.
Non-alloyed Cr/Au Ohmic contacts to N-face and Ga-face n-GaN
(2012-03-05)
Yan, Liang-Jyi
;
Kuo, Cheng Huang
;
Sheu, Jinn-Kong
;
Lee, Ming-Lun
;
Tseng, Wei-Chun
Non-alloyed Cr/Au Ohmic contacts on N-face and Ga-face n-GaN were studied. The specific contact resistances (rho(c)) of Cr/Au contacts onto the N-face and Ga-face n-GaN were as low as 2.4 x 10 (4) Omega cm(2) and 2.4 x 10(-5) Omega cm(2), respectively. Native oxide formed on the n-GaN surface was believed to be the key factor for higher rho(c). The results of X-ray photoelectron spectroscopy confirmed that n-GaN samples with different surface polarities or treated by different chemical solutions exhibited significant differences in gallium oxide content on the surface, which led to a marked difference in the rho(c) of non-alloyed Cr/Au Ohmic contacts to GaN films. (C) 2011 Elsevier B.V. All rights reserved.