Browsing by Author "Huang, Chun-Yu"

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Effect of arrangement of carbon nanotube pillars on its gas ionization characteristics
(2013-06-01)
Chang, Chia-Tsung
;
Huang, Chun-Yu
;
Li, Yu-Ren
;
Cheng, Huang-Chung
;
電子工程學系及電子研究所
The gas ionization sensors (GISs) using the carbon nanotube (CNT) pillars which has the pillar height (H) of 15 mu m with interpillar spacing (R) of 30 mu m as the cathode had been proposed for the first time to exhibit the 20 times higher field enhancement factor (beta) and the lower breakdown voltage of 350V with respect to the CNT film ones for nitrogen gas at the pressure of 0.035 Torr. As the H increased from 5 mu m to 15 mu m, the beta increased with increasing the H since the electrical field could be enhanced via the aspect ratio increment. However, as the H increased from 15 mu m to 60 mu m, the beta decreased with increasing the H owing to the increased field-screening effect. Such an optimum GIS with the CNT pillars also exhibited high sensitivity and selectivity for different kinds of gases detection as well as the good linearity for detecting the gas mixture. (C) 2013 Elsevier B.V. All rights reserved.
Improving the stability and reproducibility of the carbon nanotube gas ionization sensor by Co-Ti/Ti co-deposited catalyst layer
(2013-12-01)
Chang, Chia-Tsung
;
Huang, Chun-Yu
;
Li, Yu-Ren
;
Cheng, Huang-Chung
;
電子工程學系及電子研究所
A novel gas ionization sensor (GIS) of the carbon nanotube (CNT) film using the Co-Ti/Ti co-deposited catalyst layer had been proposed for the first time to exhibit higher stability and better reproducibility with respect to the CNT film ones with the single catalyst layer. For the proposed CNT GIS, the variation of the breakdown voltage (V-br) was less than 25% for the ten devices with the same structure measurement since the lengths of the CNT synthesized were uniform and aligned. Besides, the fluctuation of the V-br was about 14% during 1000 operation times in nitrogen at the pressure of 0.035 Torr. It was attributed to the adhesion between CNTs and the substrate could be improved since the co-deposited catalyst layer and Ti adhesion layer would be coalesced so that the Co nanoparticles would be partially immersed into Ti layer after hydrogen pretreatment. Such a CNT GIS with the co-deposited catalyst layer also exhibited high sensitivity and selectivity for different kinds of gases detection as well as the good linearity for detecting the gas mixture. (C) 2013 Elsevier B.V. All rights reserved.