Browsing by Author "Lai, Chien-Ming"

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Characteristics of high-water-uptake activated carbon/Nafion hybrid membranes for proton exchange membrane fuel cells
(2013-03-15)
Chien, Hung-Chung
;
Tsai, Li-Duan
;
Lai, Chien-Ming
;
Lin, Jiunn-Nan
;
Zhu, Chao-Yuan
A cost-effective and high-throughput method for producing high-water-uptake membranes is developed by combining high-porosity and superior-surface-area activated carbon with Nation. The resultant activated carbon/Nafion hybrid composite exhibits high water uptake and an improved proton conductivity, which can be exploited in a proton exchange membrane fuel cell (PEMFC). This hybrid membrane displays a superior performance to that of the commercial Nation 211 when used in fuel-cell measurements. Electrochemical impedance spectroscopy (EIS) is used to simulate the changes in resistance during the operation of the fuel cells and conclusively explains the improved performance of the composite membranes. (C) 2012 Elsevier B.V. All rights reserved.
Effect of NH(3) Plasma Nitridation on Hot-Carrier Instability and Low-Frequency Noise in Gd-Doped High-kappa Dielectric nMOSFETs
(2011-03-01)
Chen, Yu-Ting
;
Chen, Kun-Ming
;
Lin, Cheng-Li
;
Yeh, Wen-Kuan
;
Huang, Guo-Wei
The effects of post-NH(3) plasma nitridation on device's hot-carrier instability and low-frequency noise in the Hf-based high-kappa/metal-gate n-channel metal-oxide-semiconductor field-effect transistors (nMOSFETs) with gadolinium (Gd) cap layers are investigated. With postnitridation, the direct-current and 1/f noise characteristics can be improved apparently. Moreover, a hot-carrier stressing-induced threshold voltage shift can be also suppressed despite of a similar transconductance degradation when comparing with that in the device without nitridation. With the charge-pumping and low-frequency noise measurements, we find that the bulk-and interfacial-trap densities can be reduced with nitrogen incorporation. The reduction of bulk and interfacial traps can be contributed to the suppression of Gd diffusion into a high-kappa layer. In this paper, appropriate post-NH(3) plasma nitridation can improve the device performance and reliability and low-frequency noise for a gate-first high-kappa/metal-gate nMOSFET with a Gd cap layer.
Effect of NH3 Plasma Nitridation on Hot-Carrier Instability and Low-Frequency Noise in Gd-Doped High-kappa Dielectric nMOSFETs
(2011-03-01)
Chen, Yu-Ting
;
Chen, Kun-Ming
;
Lin, Cheng-Li
;
Yeh, Wen-Kuan
;
Huang, Guo-Wei
The effects of post-NH3 plasma nitridation on device's hot-carrier instability and low-frequency noise in the Hf-based high-kappa/metal-gate n-channel metal-oxide-semiconductor field-effect transistors (nMOSFETs) with gadolinium (Gd) cap layers are investigated. With postnitridation, the direct-current and 1/f noise characteristics can be improved apparently. Moreover, a hot-carrier stressing-induced threshold voltage shift can be also suppressed despite of a similar transconductance degradation when comparing with that in the device without nitridation. With the charge-pumping and low-frequency noise measurements, we find that the bulk-and interfacial-trap densities can be reduced with nitrogen incorporation. The reduction of bulk and interfacial traps can be contributed to the suppression of Gd diffusion into a high-kappa layer. In this paper, appropriate post-NH3 plasma nitridation can improve the device performance and reliability and low-frequency noise for a gate-first high-kappa/metal-gate nMOSFET with a Gd cap layer.
Highly hydrated Nafion/activated carbon hybrids
(2012-10-12)
Chien, Hung-Chung
;
Tsai, Li-Duan
;
Kelarakis, Antonios
;
Lai, Chien-Ming
;
Lin, Jiunn-Nan
The incorporation of highly porous activated carbon (aC) to Nafion membranes confers unprecedented levels of water uptake (4 times higher for 10 wt% aC compared to neat Nafion) at a minimal dimensional swelling and results in dramatic enhancements in ionic conductivity at low relative humidity. This behavior reveals the development of a robust network of water nanochannels formed by the carbon pores and the polymeric ionic domains which are structurally stabilized by the rigid Nafion backbone and the non-deformable aC particles. (c) 2012 Elsevier Ltd. All rights reserved.
Poly(ethylene glycol) modified activated carbon for high performance proton exchange membrane fuel cells
(2013-08-30)
Tsai, Li-Duan
;
Chien, Hung-Chung
;
Wang, Cheng-Hong
;
Lai, Chien-Ming
;
Lin, Jiunn-Nan
A high water retention membrane is developed by co-assembling poly(ethylene glycol) (PEG) grafted activated carbon (AC-PEG) with Nafion. The AC-PEG is prepared via a sol gel process. The use of PEG as a transporting medium in AC-PEG shows a largely improved water retention ability, a higher proton conductivity and a reduced swelling ratio, making it well suited for proton exchange membrane fuel cells (PEMFCs). Further, the composite membranes show improved mechanical properties at high temperature, thus ensuring the structural stability of membranes during the fuel cell operation. Compositional optimized AC-PEG/Nafion composite membrane (15 wt% compared to Nafion) demonstrates a better performance than the commercially available counterpart, Nafion 212, in fuel cell measurements. To identify the key factor of the improved performance, current interrupt technique is used to quantitatively verify the changes of resistance under different relative humidity environment. Copyright (C) 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.