Research On The Synthesis And Optoelectrics Properties Of Graphene By CVD

Graphene was found by British scientists in 2004, which now is a focus of research in physics, chemistry, materials fileds. Graphene has many advantages, it is the thinnest, hardest novel material with super electronical and thermal conductivities. It can be combined with metals, metal oxides and so on, with promising application in Lithium ion battery electrode materials, thin film transistor, sensor, semiconductor devices, transparent display touch screen etc. In the past ten years, the research of graphene had taken a leap, national research institutions around the world and multinational companies have done their best to research the graphene and its applications.Copper and nickel was uesed respectively as the substrate for CVD method to grow graphene, to explore the influences of growth parameters on the sysnthesis of graphene and find the optimal growth parameters. At last, I grew high quality（weak D peak）, several layers（3⁴ layers） graphene with large area（2×2cm） successfully.Using Cu as the substrate to grow graphene by CVD, exploring the influences of process parameters on the synthesis of graphene.I found once the growth time exceeds a certain time limits, the self-limited growth theory on Cu surface will no longer be applicable. And an appropriate cooling rate is a must for graphene growth on Cu substrate by CVD, slow cooling rate is an obstacle for the graphene growth with large area and high quality. By optimizing the growth parameters, I synthesised less layers graphene with large area successfully. Furthermore I analyzed the relationship between the graphene layers and its photoelectric propertiesUsing Ni as the substrate to grow graphene by CVD, exploring the influences of process parameters on the growth of graphene. I found that a slow cooling rate will not lead to multi-layer graphene or graphite, and we can seldom found the trace of carbon. By improving the process parameters, less layers graphene with large area on Ni foil surface was successfully obtained. Furthermore, I characterized its transmittance and took advantage of its transmittance to analyze the layers.Comparing graphene growth on Cu foil and Ni foil to find the advantages and disadvantages respectivly. I found that the grpahene growth on Cu foil is more difficult than its growth on Ni foil, but usually the graphene on Cu foil tends to be less layers. The H₂ flow has strong etching effect to the graphene on Cu foil; while it almost never has etching effect to the graphene growed on Ni foil. There are too much defects in the graphene growed on Cu foil and the quality is very high for graphene growed on Ni foil.