熱與光對化學汽相成長奈米碳管場發射的效應及其發光元件應用研究

Study of thermal and optical effect on electron field emission properties of carbon nanotubes for emitter applications.

謝昀朔(Yun-Shuo Hsieh)

指導教授 ： 鄭秀鳳

國立臺灣師範大學/理學院/物理學系在職進修碩士班/碩士(2002年)

摘要

本研究利用微波電漿輔助化學汽相沉積法成長奈米碳管於鐵針針尖，採用製程參數及所得結果包括(1)改變不同氣體總壓成長奈米碳管由低壓至高壓碳管直徑有漸大的趨勢，(2)有機鐵催化劑對成長之奈米碳管均勻度有顯著的影響，不同氣體成長之奈米碳管也有不同的型態，及(3)以石墨粉及鑽石粉為碳源在適當的壓力及溫度條件下可以成長奈米碳管。
在微波電漿輔助化學汽相沉積法成長奈米碳管之臨場電漿發射光譜研究中，改變不同氣體總壓擷取電漿可見光發射光譜，分析不同壓力下成長奈米碳管的電漿中之物種及計算電漿溫度，藉以獲得成長奈米碳管最佳化的參數條件，進一步以固─液─固成長模型解釋了微波輔助化學汽相沈積法合成奈米碳管於鐵針針尖的成長機制。
在熱與光對奈米碳管之電子場發射特性影響實驗中，加熱與照射雷射光對奈米碳管場發射特性都會產生明顯且不可回復之影響。另外，初步嘗試利用掃描穿隧電子顯微鏡(STM)觀察碳管，可得解析度不錯之表面微結構，最後，研製奈米碳管引發綠光之元件雛形，顯示本研究所合成奈米碳管具有應用於場發射元件之潛力。

關鍵字

奈米碳管 ； 電子場發射 ； 化學汽相沉積法

並列摘要

In this thesis, the microwave plasma enhanced chemical vapor deposition method was used to synthesize carbon nanotubes on the tip of iron needle. The morphology of the carbon nanotubes changed with the gas species and the diameters of the carbon nanotubes increased with the gas pressure in the chamber. The organic iron catalysts precoated on the tip pronouncedly improved the carbon nanotubes grow uniformity. Moreover, carbon nanotubes were synthesized by using graphite powder and diamond powder as the carbon sources.
Optical emission spectra of the microwave enhanced plasma in the synthesizing process were analyzed to optimize the growing process and to investigate the growth mechanism. From the gas species and the corresponding plasma temperature calculated from the spectra, solid-liquid-solid model was proposed to explain the growing mechanism for the carbon nanotubes on the tip of iron needle. The topography image of carbon nanotubes is characterized by scanning tunneling microscopy.
The field emission properties are markedly influenced by heating and laser irradiation. Finally, a prototype electron field emitter was demonstrated, which shows that carbon nanotubes possess good potential for the application on the field emission devices.

並列關鍵字

carbon nanotubes ； electron field emission ； CVD

參考文獻

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