| Summary: | 碩士 === 國立臺北科技大學 === 材料科學與工程研究所 === 99 === Graphene is the attractive new film material for the past few years. The differences between graphene and graphite are that graphene is the quasi-2D materials with excellent properties such as high mechanical stress, high conductivity, high specific surface area, and high electron mobility. For flexible transparent conductive films and related optoelectronic products, graphene is with large potential on them.
The principle of the catalytic reaction of graphite decomposed into carbon atoms in the transition metals at high temperatures was applied in this study. Samples with proper ratio of graphite powder and trasition metal powder were mixed and pressed into a cylindrical pellet which was sealed into the quartz tube with vacuum and argon atmosphere. The samples were then heated by induction heating equipment with various power and time conditions. A carbon atom would be precipitated from the solid solution and formed a large area graphite film on the surface of the bulk samples during a short time. As compared with the traditional synthesis methods, the induction heating can enhance the efficiency of fabrication process of graphite films.
The physical properties of the graphite films were investigated by the optical microscopy, scanning electronic microscopy, Raman spectroscopy and Hall meter. Large area graphite films were observed in the bulk samples. The morphology of films with wrinkle defects which is at the edge of the graphite grain boundary could be formed during various process condictions. Using the statistical methods, the density of the wrinkle could be reduced with the cooling rate. By Raman spectrum, it discovered the graphite films formed by multi-layer graphene that the G peak, which is quite sharp, is at the position of 1580 cm-1, and the 2D peak, which is a characteristics of graphene, is at about 2750 cm-1. Finally we analyze the exfoliating graphite film by x-ray diffraction and it is showed a 2H-type crystal structure in these samples.
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