石墨烯是由碳原子所組成，僅僅只有單原子層厚度的準二維材料，具有良好的機械強度、化學穩定性以及快速的電子遷移率，因此在軟性透明導電薄膜的應用上受到重視。

雖然單層石墨烯具有快速的電子遷移率，但是受限於自由電子數量的不足，因此無法真正符合透明導電薄膜的應用。透過增加石墨烯的層數以增加自由電子的數量經過計算是可行的。

根據計算結果，10~20層的數層石墨烯是最適合用在透明導電薄膜的範圍。因此本研究利用鎳箔當作催化金屬和支撐基材，透過化學氣相沉積法，成長數層石墨烯。透過改變稀釋氣體流量的控制、通入碳源氣體的時間，在最佳化的參數下，可成長出高覆蓋率以及大面積(公分等級)的FLG，並且控制層數在1~30層內，並且將此最佳製程參數定為實驗室FLG的標準製程。

為了釐清石墨烯在化學氣相沉積製程成長機制的問題，針對相同位置的數層石墨烯/鎳試片，利用不同的分析儀器，包括拉曼光譜儀的一維以及二維掃描分析、掃描式電子顯微鏡、原子力顯微鏡、能量散佈光譜儀、背向電子散射繞射光譜儀的二維掃描分析，進行最直接的量測與分析，提供石墨烯在成長機制中，最有力的實驗分析結果。此外，針對析出成長機制進行驗證的實驗。根據我們的實驗以及分析結果，析出機制並無法完全解釋實驗結果，沉積機制可能是比較適合的成長機制。

在轉移部份，透過稀鹽酸水溶液的蝕刻將數層石墨烯從鎳箔轉移至二氧化矽/矽試片上，並且針對相同的位置進行包括拉曼光譜儀、掃描式電子顯微鏡、原子力顯微鏡、能量散佈光譜儀、。從原子力顯微鏡分析結果，標準製程下製備的數層石墨烯厚度約數奈米。

在製備石墨烯軟性透明導電薄膜部份，利用鎳箔軟而薄的特性，透過符合工業應用的捲繞傳輸轉移製程，將標準製程的數層石墨烯轉移至乙烯-醋酸乙烯共聚物/ (聚對苯二甲二乙酯上，完成軟性透明導電薄膜，在最佳的製程條件下，可得到在波長550 nm穿透率50~55 %，片電阻約數千Ω/□的軟性透明導電薄膜。

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/□.

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