奈米碳管的聲子,吸附性質及其新穎的合成技術

Phonon and adsorption properties of aggregated carbon nanotubes and novel productions for tubular graphite and individual graphenes

許景棟(Ching-Tung Hsu)

指導教授 ： 徐文光

國立清華大學/工學院/材料科學工程學系/博士(2008年)

摘要

這篇論文第3,4章內容在探討當奈米碳管聚集在一起時，碳管間的接觸對熱容及熱傳的影響。第3章，我們使用電腦模擬利用密度泛函理論，我們算出了當奈米碳管聚集在一起時，由於管的堆積造成整個管束剛性增加，聲子的震盪能量因而變高，造成低能聲子震動時所需要的能量增加，低溫時熱容量下降。 第4章，我們實做實驗，結果顯示當碳管隨意堆積時，碳管間的接觸點是熱傳的頻頸，聲子的倒逆過程(Umklapp processes)造成熱不易流出碳管膜。第5章，我們臨場下(in-situ)量測氣體離子在奈米碳管膜(SWCNT mat)上吸附，擴散，脫附的行為並利用電腦模擬做詳細的研究，結果顯示當氣體離子移動到碳管間的接觸點時，會使碳管膜的電阻有明顯的下降。第6,7章，我們利用電擊棒來生長碳管，奈米纖維(nanofiber)及石墨烯（graphene）。碳管及奈米纖維在這裡是藉著化學反應合成，而石墨烯是利用電斥力，使石墨片從石墨棒上分裂開來，屬於物理性合成。

關鍵字

奈米碳管 ； 熱學性質 ； 聲子 ； 合成技術 ； 石墨烯 ； 管間作用

並列摘要

This thesis is devoted to probe into the influences of the intertube interactions or
intertube junctions on the physical properties of SWCNT mat, such as thermal properties, electronic transporting properties, and mechanical properties.
This thesis is divided into few parts:
In the chapter 1, an introduction to this thesis is given.
In the chapter 2, literature review and experiment method are shown in this chapter.
In the chapter 3, we use First Principe Density Function Theory to simulate the thermal property on carbon nanotube. SWCNTs packed into bundle exhibit an increase in tube rigidity and up-shift of phonon frequency by intertube force.
In the chapter 4, experiments are carried out to show how thermal conductivity is influenced by internanotube junctions.
In the chapter 5, experiments are performed to demonstrate the effects of ion gas adsorption, migration and desorption on carbon nanotubes. First Principe DFT calculations are given to explain the results. It is shown that the adsorptions at internanotube junctions play an important role in whole resistance of SWCNT mat.
In the chapter 6, Corona discharge is used as a novel way to produce carbon nanotubes, nanofibers, graphene and porous carbon structure.
In the chapter 7, Corona discharge is used as a new method to produce graphene and First Principe DFT calculations have been carried out to evaluate the graphene property.

並列關鍵字

carbon nanotube ； thermal properties ； phonon ； Synthesis ； graphene ； intertube interactions

參考文獻

1. Curl, R.F., Rev. Mod. Phys, 1997. 69: p. 691.

2. Kroto, H., Rev. Mod. Phys, 1997. 69: p. 703.

3. Smalley, R.E., Rev. Mod. Phys, 1997. 69: p. 723.

4. Iijima, s., Nature, 1991. 56: p. 354.

5. R. H. Baughman, A.A.Z., and W. A. de Heer, Carbon nanotubes - the route toward applications. Science, 2002. , vol. 297: p. 787-792.