合成並探討單層奈米碳管的特性與場發射性質

Synthesis, Characterization and Field emission of Single Wall Carbon Nanotubes

楊裕祥(Yu-Hsiang Yang)

指導教授 ： 施漢章 ； 張一熙

國立清華大學/工學院/材料科學工程學系/碩士(2006年)

摘要

本工作主要在研究利用化學氣相沈積法熱裂解乙醇來合成單層奈米碳管並研究其特性，以鐵及鉬為催化劑沈積在氧化鎂粉末上，探討不同表面積的溶膠凝膠氧化鎂催化劑載體對於合成單層奈米碳管的影響，本實驗製程在900°C下通入乙醇維持氣壓5torr合成單層奈米碳管，FESEM表面形貌觀察中發現單層碳管結構有呈現片狀的特別結構，由HRTEM觀察中發現聚集成束的單層奈米碳管管徑分布為0.6-1.6 nm，獨立的單層奈米碳管管徑分布為2.4-6 nm，從Raman光譜分析中發現本實驗合成之單層碳管有很低的ID/IG值顯示出有不錯的石墨化程度而且僅含有少量的非晶質碳，並利用RBM特性峰計算出單層碳管管徑分布為0.6-1.6 nm，熱重分析中發現利用乙醇作為碳源僅僅含有少於8.7%非晶質碳顯示出乙醇可以提升單層奈米碳管的純度，在電子場發射方面則擁有非常低的起始電場強度(Eto=0.008V/μm)及臨界電場強度(Ethr=0.07 V/μm)顯示出本實驗的產物擁有很好的電子場發射性質。

關鍵字

單層碳管 ； 場發射 ； 溶膠凝膠法

並列摘要

In this work, single wall carbon nanotubes (SWNTs) were synthesized by the pyrolysis of alcohol in a CVD process and characterized. The catalyst was fabricated by depositing Fe and Mo particles on the surface of MgO powders by sol-gel methode. In this experiment, the effects of different surface areas of the catalyst support were discussed. SWNTs were synthesized on the surface of Fe-Mo/MgO under 5torr C2H5OH atmosphere at 900°C. From FESEM observation, SWNTs were found flake-like structure. SWNTs have diameters in the range of 0.6-1.6 nm in bundles and in the range of 2.4-6 nm for isolated SWNTs. Raman spectrum shows that SWNTs in this experiment have low ID/IG value which means high purity and high quality of SWNTs, and that SWNTs have diameters in the range of 0.6-1.6 nm as calculated from the RBM peaks. From DTA-TGA analysis, high-purity of SWNTs was demonstrated. The extremely low turn-on field (Eto=0.008 V/μm) and threshold field (Ethr=0.07 V/μm) show that the SWNTs have excellent performance on electron field emission.

並列關鍵字

SWNT ； Field emission ； Sol-gel MgO

參考文獻

[1] S.L. Sung, S.H. Tsai, C.H. Tseng, F.K. Chiang, X.W. Liu, and H.C. Shih, “A Novel Form of Carbon Nitride – Well-Aligned Carbon Nitride Nanotubes and Their Characterization”, J. Mater. Res., Vol. 15, pp. 502-510 (2000).

[2] S.H. Tsai, F.K. Chiang, T.G. Tsai, F.S. Shieu, and H.C. Shih, “Synthesis and Characterization of Aligned Amorphous Carbon Nanotubes by Electron Cyclotron Resonance Plasma”, Thin Solid Films, Vol. 366, pp. 11-15 (2000).

[3] S.H. Tsai, C.T. Shiu, W.J. Jong, and H.C. Shih, “The Welding of Carbon Nanotubes”, Carbon, Vol. 38, pp.1879-1902 (2000).

[4] S.H. Tsai, C.T. Shiu, S.H. Lai, and H.C. Shih, “Tubes on Tube – a Novel Form of Aligned Carbon Nanotubes”, Carbon, Vol. 40, pp. 1597-1600 (2002).

[6] L.H. Chan, K.H. Hong, S.H. Lai, X.W. Liu, and H.C. Shih, “The Formation and Characterization of Palladium Nanowires in Growing Carbon Nanotubes Using Microwave Plasma-enhanced Chemical Vapor Deposition”, Thin Solid Films, Vol. 423, pp. 27-32 (2003).