奈米碳管的成長機制與場發射特性研究

Study on Growth Mechanism and Field Emission Properties of Carbon Nanotubes

曹佑民(You-Ming Tsau)

指導教授 ： 鄭秀鳳

國立臺灣師範大學/理學院/物理學系/碩士(2001年)

摘要

本篇論文共分為三個部份，在第一個部份「選區成長奈米碳管暨成長機制研究」中，使用兩種方法成長奈米碳管(1)微波引致放電製程、(2)鑽石薄膜高壓放電製程。微波引致放電製程能控制奈米碳管成長於電視映像管電子槍的發射頭頂端，所成長的奈米碳管型態，會隨著改變不同催化劑、改變成長時間而發生不同的變化，且場發射亦會因此而改變。這一個製程的奈米碳管成長機制能夠以金屬催化劑的「擴散理論」以及「階段-流成長(step-flow growth)」說明。而鑽石薄膜高壓放電製程，在不使用催化劑下，施加不同電壓，成功成長奈米碳管於選定的放電點。這個製程的奈米碳管成長機制則較類似傳統弧光放電製程。
第二個部份「微波輔助法成長奈米碳管之臨場可見光發射光譜(OES)研究」，改變製程中的混合氣體比例、微波瓦數，再利用臨場擷取微波輔助法成長奈米碳管時所產生電漿的可見光發射光譜，分析奈米碳管成長時電漿中的物種及電漿溫度，得到在此製程中成長奈米碳管最適當的成長參數條件。
第三個部份「奈米碳管場發射特性研究」，研究溫度及雷射對於奈米碳管場發射的影響，並且藉由量測樣品的傅利葉轉換紅外光(FTIR)光譜分析樣品的介電常數、導電率，比較場發射特性與介電常數、導電率間的關係。

關鍵字

奈米碳管 ； 場發射 ； 成長機制

並列摘要

In this thesis, it includes three major topics: local area growth control, In-situ spectroscopic characterization, and electron field emission properties of carbon nanotubes (CNTs). In order to control the growth area, “microwave inducing arc discharge” and “high-voltage arc discharge on diamond thin films” were used. It has been successful to grow the carbon nanotubes with gas or liquid catalysts by microwave inducing arc discharge method. The growth mechanism of CNTs by using microwave inducing arc discharge method can be explained by “diffusion growth model” and “step-flow growth model”. By using high-voltage arc discharge method, it can grow the carbon nanotubes on the diamond thin films without catalysts. The growth mechanism of CNTs on diamond thin films by using high-voltage arc discharge is similar to the growth of carbon nanotubes by traditional arc discharge method.
In order to study the growth mechanism of carbon nanotubes, microwave plasma enhanced CVD was utilized, and the In-situ spectroscopic characterization was proceeded during the growing process. The optical emission spectrum of the microwave enhanced plasma was diagnosed by the optical multi-channel analyzer (OMA) during the growing process. It provides the information about the species and the growth temperature, which are helpful to understand the growth mechanism of CNTs.
The electron field emission properties of carbon nanotubes, which were synthesized by the microwave heating chemical vaper deportations (MHCVD) method, was measured at various temperatures with lased-irradiation-induced process. The electron field emission properties were improved during the lased-irradiation-induced process. The electrical property of carbon nanotubes was evaluated by using Fourier Transform Infrared (FTIR) spectroscopy. The electron field emission properties and electrical properties were investigated.

並列關鍵字

Carbon Nanotubes ； Field Emission ； Growth Mechanism

參考文獻

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