奈米碳管電漿後處理之拉曼性質研究

Abstract

本研究目的主要在探討奈米碳管進行電漿後處理之拉曼性質研究。實驗方法為使用熱化學氣相沉積法合成奈米碳管，於電漿後處理過程中添加不同之反應氣體，並使用拉曼光譜儀量測奈米碳管品質指數。最後，使用穿透式電子顯微鏡分析奈米碳管於不同緩衝層之微細結構及成長機制。 其結果顯示：(1) 由熱化學氣相沉積法所合成之奈米碳管，緩衝層Ni 7nm / TiN 20nm / Si sub.在提高處理溫度時，可獲得最佳成長厚度。(2) 由拉曼分析可得知，奈米碳管經過100W電漿後處理其結構破壞程度以添加O2 為最強；經過200W的電漿後處理，以添加NH3對結構破壞程度最強；在300W時添加CF4+O2對結構破壞程度最強。(3) 經穿透式電子顯微鏡分析奈米碳管於不同緩衝層之成長機制為vapor-liquid-solid，在較低的CN和較高的H形式條件下，表面擴散壓制內部擴散而使得竹節狀結構並不明顯。

This research used the best parameters of carbon nanotubes to experiment with plasma post-treatment by PECVD and added different reactive gases with plasma. At last we measured quality index of carbon nanotubes by Raman spectrometer and analyzed growth mechanism by Transmission Electron Microscope. The answers showed : First, that parameter of Ni 7nm / TiN 20nm / Si sub. had been increased thickness is four times than no buffer layer by adding temperatures of pre-treatment and post-treatment by thermal-CVD. Second, O2 is the most damageable than NH3 and H2 for structure after 100W in analytic aspects of Raman spectrum by plasma post- treatment. Similarly NH3 is the most damageable than others after 200W and CF4+O2 is the most damageable than O2、CF4 after 300W. Third, using TEM investigations showed that CN and H radicals play very important role in both the V-L-S growth mechanism and microstructures of carbon nanotubes.