Synthesis Of Carbon Nanotubes Arrays And The Phase Transformation Of Carbon Nanotubes Into Diamond

Metal nano-film is the effective catalyst for synthesis of carbon nanotube and highly oriented carbon nanotube array in CVD.The metal films are synthesized generally by PVD, and substrate temperature determines the growth mode and surface morphology of the film thus affect catalytic performance of the film. However, the catalytic performance of the films deposited under different temperatures is still poorly characterized.Pretreatment in NH3 before CVD can promote the growth of aligned carbon nanotubes, but because of the differences of laboratory equipment and parameters, no consensus on the mechanism and significance of NH3.In this thesis, thin Fe films were deposited on Si wafers in a metal vapor vacuum arc (MEVVA) ion deposition system under different substrate temperatures, and then carbon nanotubes were deposited by thermal CVD method used Fe nano-films as the catalyst after pretreatment in NH3 environment. The forms of Fe thin film growth mode and the surface morphology of the film were investigated. The effects of substrate temperatures during PVD on the catalytic performance of the Fe films, and the importance of NH3 pretreatment for growth and directionality of carbon nanotubes had been discussed.The experiments and theory prove that carbon nanotubes will transform into diamond. Relevant scholars succeeded in obtaining the diamond nano-particle even diamond nanorods by the induction of radiofrequency hydrogen plasma. Microwave plasma with higher ion energy and ion density than the DC-RF plasma, and the microwave-assisted CVD is wildly used in the synthesis of diamond files, so using this efficient plasma for the transformation of carbon nanotubes into diamond is very significant.In this thesis, we use multi-functional thin plasma devices to treat the carbon nanotubes for a long time, the condition of etching and phase transformation of carbon nanotubes had been studied, so the method for phase transformation of carbon nanotubes into diamond by microwave hydrogen plasma had been tried, what can provides experimental references.