以不鏽鋼網輔助微波電漿束化學氣相沉積系統成長奈米碳管及其表面電性分析

以微波電漿束化學氣相沉積法成長奈米碳管，利用不鏽鋼網減少離子轟擊效應，輔助成長厚度更高的碳管薄膜。生長碳管的最低功率為690 W，最長123.9 um的碳管於800 W成長。最佳的N2和H2比例為0.33，800 W、1000 W成長的碳管直徑為26.40 nm和28.56 nm、高度為123.9 um和87.63 um。氣體比例為0.75，碳管直徑增加至55.89 nm，持續提高至3，碳管直徑將縮短至45.50 nm。場發射量測，碳管起始電場最低為0.71 V/um，有碳管直徑愈小、ID/IG愈高、起始電場愈低的趨勢，薄膜厚度對場發射影響不如直徑、ID/IG明顯，由碳管高度、直徑和分佈密度推得形貌因子，形貌因子愈大、起始電場愈低。電潤濕實驗，對象為奈米碳管和碳類材料，疏水性轉化至親水性的最小轉換電壓分別為4 V和23 V，碳管試片的最大接觸角減少量為23.9°-84.7°，碳類材料只有3.4°-4.6°，碳管高度和直徑相當的試片，得到ID/IG愈高，轉換電壓愈小的趨勢。相似結構的碳管之性能比較，能由ID/IG推估場發射的起始電場愈低、電潤濕的轉換電壓愈高。

關鍵字

奈米碳管；不鏽鋼網；場發射；電潤濕

並列摘要

For growing thicker carbon nanotubes (CNTs) films, this study placed stainless mesh to reduce ion bombard effect produced by plasma. The CNTs growth system was microwave plasma jet chemical vapor deposition (MPJCVD), and placement of meshes were top and inner of quartz box. Under the same pressure and growth time, the research controlled microwave power, CH4 flow rate, ratio of N2 and H2 to study CNT length, diameter and structure. With the aid of mesh, the results showed the lowest power for growing CNTs was 690 W and the longest height was 123.9 μm at 800 W. Under the same microwave power, the best ratio of N2 and H2 was 0.33 for CNTs film growth. The thickest CNTs films in group A and B were 123.9 μm and 87.63 μm, and the diameters were 26.40 nm and 28.56 nm. According to field emission experiment, the data showed thinner diameter, higher ID/IG of CNTs would decrease turn-on field, and these factors had more positive effect than thickness. In this study, half CNTs samples had the lower turn-on field, and the values ranged from 0.71 V/μm to 0.78 V/μm. In electrowetting measurement, CNT was compared with carbon materials (carbon black, carbon nanobead and carbon nanowalled). When their hydrophobic properties became hydrophilic, the values of changed contact angle of CNTs ranged from 23.9° to 84.7° and 3.4°-4.6° for carbon materials. In compare with similar CNT morphology, these samples showed higher ID/IG CNT had lower electrowetting voltage. Combining the CNT relations of field emission and electrowetting, this study showed higher ID/IG CNT had lower turn-on field and higher electrowetting voltage.

並列關鍵字

CNT ； stainless steel mesh ； field emission ； electrowetting

參考文獻

[49] 張靖郁，利用電漿放射光譜診斷MPJCVD系統成長奈米晶鑽石膜及其光電導特性研究，博士論文，國立臺北科技大學機電科技研究所，台北，2008。

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[2] I. Jang, H. S. Uh, H.I. Cho, W. Lee and J.P. Hong, "Characteristics of carbon nanotubes grown by mesh-inserted plasma-enhanced chemical vapor deposition," Carbon, vol. 45, 2007, pp.3015-3021.

[3] H. F. Chenga, Y. M. Tsau, T. Y. Chang, T. S. Lai, T. F. Kuo and I N. Lin, "Electron field emission properties of carbon nanotubes grown on iron needles," Diamond and Related Materials, vol. 12, 2003, pp.486–489.

[4] L. V. W. Randall and J. H. Lee, "Carbon nanotube synthesis upon stainless steel meshes," Carbon, vol. 41, 2003, pp.659–672.

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以不鏽鋼網輔助微波電漿束化學氣相沉積系統成長奈米碳管及其表面電性分析

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