Abstract
Graphene, a 2D-planner material which is composed of carbons with only one-atom-thick has a stable chemical stability, excellent electron mobility, and high mechanical strength. Therefore, graphene has paid more and more attention for the application on flexible transparent conductive thin film. However, due to the lower free electron concentration (or free electron quantity) of Single-layer graphene, it’s difficult to apply on the flexible transparent conductive thin film. According to our calculation, the free electron quantity can be enhanced by adding the layers of graphene. The optimum layers of graphene for transparent conductive thin film is about 10~20 layers by our calcutation. Therefore, we have synthesized few-layer graphene (FLG) on nickel foil by chemical vapor deposition method. By changing the amounts of diluation gases and the times of carbon sources, we can synthesize large area (centimeter scale) FLG with high coverage on nickel foil under optimum condition. The numbers of layers is controlled for 1~30 layers. To further investigate the growth mechanism of graphene in chemical vapor deposition method, we analyze the FLG/Ni with Raman mapping, SEM, AFM, EDX, and the EBSD on the same location. Therefore, we can provide the direct experimental analysis results. The preliminary experimental results can’t be explained by segregation growth mechanism and deposition growth mechanism would be an appropriate for our cases. In transfer sections, FLG can be transferred by etching nickel foil with dilute HCl solution to SiO2/Si. FLG/SiO2/Si sample is also analyzed with Raman spectra, SEM, AFM, and EDX on the same location. The thickness of our FLG is about several nm by AFM analysis results. To synthesize FLG flexible transparent conductive thin film, FLG is transferred by roll-to-roll (R2R) process after CVD process. The transmittance and sheet resistance for our best FLG flexible transparent conductive thin films are 50~55 % and several thounds Ω/□.