| Summary: | 碩士 === 義守大學 === 材料科學與工程學系碩士班 === 95 === There are very great relations between CNT growth and metal catalysts, but most study had fabricated CNT with catalyst thin films in the literature. In the study, we wants to probe into the effect of structure and composition of catalyst on the growth of CNT, so we prepared Ni-P films and NiO-YSZ to grow CNT by MPCVD. In order to apply to glass substrate or PI substrate, so the process temperature must be reduced under 450 ℃. In addition, we explored the different process conditions of MPCVD impact on the diameter, length and numbers of CNT and CNF.
The result shows, we can grow CNT and CNF on NiO-YSZ by MPCVD when the mole percentage of NiO is in the range of 5~35 %, but the content of NiO doesn’t apparently influence the diameter, density and numbers of CNT as well as CNF. The inner diameter of NiO-YSZ-derived CNT is about 5~10 nm and the outside diameter decided by the number of carbon layer is about 10~30 nm. When the NiO content is 15 mol% in NiO-YSZ and the growth power is 600 W for 12 mins, the maximum percentage of CNT is obtained and the value is 64 %. As the content of NiO is 8mol % and the growth power is 600 W for 12mins, the percentage of CNF is 82 %.
The crystallization of the Ni-P is influenced by heat treatment condition and thickness. After heat treatment(500 ℃ for 3hr in air), the Ni-P film transform to NiO when its thickness is below 40 nm, and Ni-P film transform to NiO and Ni2P when its thickness is over 40 nm. As the NiO film is used as catalyst, the percentage of CNT is 46 %. In contrast, the NiO-Ni2P film is used, the percentage of CNT is 39 %. According to TEM observation, it is argued that the CNT growth mechanisms of Ni-P films are of the tip-root growth.
Furthermore, it is observed that, the carbon layers structure of NiO-YSZ-derived CNT are relatively perfect and the inner diameter of CNT are similar. However, there exist a little spiral CNF for Ni-P film. Because PI is not able to resist the high temperature itself and it is not good adhesion with the Ni-P films, so we can not grow CNT on PI.
|
|---|
