Browsing by Author "Shen, GR"

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Comparative study of Ni-P-diamond and Ni-P-CNT nanocomposite films
(2006)
Chao, TY
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Shen, GR
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Cheng, YT
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電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
Ni-P-diamond and Ni-P carbon nanotube (CNT) nanocomposite films have been synthesized and compared in this paper. Because diamond has different shapes and sizes than CNTs, the nanocomposite films exhibit distinct characteristics. Nanoindentation measurements show that the Young's modulus and hardness of the Ni-P-CNT nanocomposite film electroplated in a bath with 0.028 g/L CNTs increase to 665.9 +/- 29.5 GPa and 28.9 +/- 4.22 GPa, respectively, which is about four times larger than that of pure nickel. On the contrary, the modulus and hardness of the Ni-P-diamond nanocomposite films decrease with the incorporation of the nanodiamond powders due to the formation of voids and cracks, even though both diamond and CNTs have similar Young's modulus and hardness. For the Ni-P-diamond film plated in the bath with 2.0 g/ L nanodiamonds, the values are reduced to 110.5 +/- 4.3 and 2.3 +/- 0.1 GPa. Nevertheless, the electrothermal actuators made of both Ni-P-CNT and Ni-P-diamond composites can provide four times the maximum elongation, larger than that made of pure nickel. With the same displacement, the input power of the nanocomposite actuators is much less than that of the pure Ni one. This study reveals potential applications for nano/microelectromechanical systems fabrication using both Ni-P-diamond and Ni-P-CNT nanocomposites due to their distinctive physical properties and compatibility with contemporary complementary metal oxide semiconductor manufacturing processes. (c) 2005 The Electrochemical Society. [DOI: 10.1149/ 1.2133324] All rights reserved.
Ni-P-CNTs nanocomposite film for MEMS applications
(2004)
Shen, GR
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Tsai, LN
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Chao, TY
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Cheng, YT
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Lin, TK
A Ni-P-CNTs (electroless phosphorus nickel-carbon nanotubes) nanocomposite film synthesis and related processes for MEMS device fabrication have been successfully developed and presented in this paper. With a special acid oxidative method, a well-dispersed nickel-CNTs colloidal solution has been produced without any aggregation, very suitable for microstructure fabrication. The nano-indentation measurement indicates that the Young's modulus and hardness of the Ni-P-CNTs nanocomposite film plated in the bath with 0.028g/L CNTs can greatly increase up to 666Pa and 29GPa, respectively, which is four times larger than that of pure nickel: The performance improvement of the electro-thermal microactuator made of the nanocomposite, including device strength and power efficient, have been proved similar to the Ni-diamond composites [1]. With the same power input, the device can provide 4 times elongation longer than that made of pure nickel. The mechanical strength of the actuator can also be enhanced to sustain the input power with two times larger than the pure one.
Performance improvement of an electrothermal microactuator fabricated using Ni-diamond nanocomposite
(2006-02-01)
Tsai, LN
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Shen, GR
;
Cheng, YT
;
Hsu, W
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電子工程學系及電子研究所
In this paper, a low-temperature stress-free electrolytic nickel (EL) deposition process with added dispersed diamond nanoparticles (diameter < 0.5 mu m) is developed to synthesize Ni-diamond nanocomposite for fabricating electrothermal microactuators. Device characterization reveals dramatic performance improvements in the electrothermal microactuator that is made of the nanocomposite, including a reduction in the input power requirement and enhanced operation reliability. In comparison with the microactuator made of pure nickel, the nanocomposite one can save about 73% the power for a 3 mu m output displacement and have a longer reversible displacement range, which is prolonged from 1.8 mu m to more than 3 mu m. Furthermore, the nanocomposite device exhibits no performance degradation after more than 100 testing cycles in the reversible regime. The enhancements increase with the incorporation of the nanodiamond in a nickel matrix, so the Ni-diamond nanocomposite has potential for application in MEMS fabrication.
Power and reliability improvement of an electro-thermal microactuator using Ni-diamond nanocomposite
(2004)
Tsai, LN
;
Shen, GR
;
Cheng, YT
;
Hsu, W
;
電子工程學系及電子研究所
Here a low-temperature stress-free electrolytic nickel (EL) deposition process with the addition of uniformly dispersed diamond nanoparticles (diameter < 0.5 mum) is propose to fabricate cantilevers and electro-thermal microactuators to demonstrate the improvement of the device on reducing input power requirement and enhancing operation reliability. The fabrication results show that the nanodiamond particles are successfully dispersed in the electroplating nickel layers. By calibrating the resonant frequencies of nickel cantilevers with different concentrations of diamond nanoparticles, the E/pratio of cantilevers can be enhanced 7.1 times with diamond nanoparticles of 2 g/l in the proposed electrolytic nickel (EL) deposition process. From displacement tests, the electro-thermal microactuator with nanodiamond particles of 2 g/l reduces 73% power requirement of pure nickel device needed at the same output displacement of 3 mum. Also, the reversible displacement range is found to be expanded from 1.8 mum to 3 mum by adding nanodiamond particles of 2 g/l in the nickel electro-thermal microactuators.
Synthesis and characterization of Ni-P-CNT's nanocomposite film for MEMS applications
(2005-09-01)
Shen, GR
;
Cheng, YT
;
Tsai, LN
;
機械工程學系
;
電子工程學系及電子研究所
An electroless phosphorus nickel-carbon nanotube's (Ni-P-CNT) nanocomposite film synthesis and related process for microelectromechanical systems device fabrication have been successfully developed and presented in this paper. With a special acid oxidative method, a well-dispersed nickel-CNT's colloidal solution has been produced without any aggregation, which is very suitable for microstructure fabrication. The nanoindentation measurement indicates that the Young's modulus and hardness of the Ni-P-CNT's nanocomposite film plated in the bath with 0.028-g/L CNTs can greatly increase up to 665.9 and 28.9 GPa, respectively, which are approximately four times larger than that of pure nickel. Moreover, the content of CNTs in the Ni-P-CNT's films is measured by an elemental analyzer. Via the electrical resistivity measurement using a four-point probe, it is found that the electrical property of the nanocomposite film can be well characterized using a Maxwell-Wagner model for a two-phase mixture. The performance improvements of the electrothermal microactuator made of the nanocomposite, including device strength and power efficiency, have been proven similar to the actuator made of the Ni-diamond composites by electrolytic plating by Tsai et al, but with more efficiency and higher strength than the Ni-diamond device does.