| 摘要: | 石墨烯(Graphene)，只有單一個原子層厚度(0.34 nm)的石墨薄膜，具有優異的載子傳輸速率(200,000 cm2V-1s-1)、機械強度(1,100 GPa)、光穿透率(>97%)、化學穩定性、耐高曲度彎折，被認為是能取代ITO的候選材料之一，不僅能廣泛運用於穿戴式元件開發，需在嚴苛環境下的元件(如太陽能電光電板)也能提高運作壽命。化學氣相沉積法(Chemical Vapor Deposition, CVD)於過渡金屬基板上成長石墨烯薄膜的為目前的主流方法，具有大面積及高均勻性的優點，相當具有工業化的潛力，但化學氣相沉積法成本較高，為了降低其成本以利工業化生產，本實驗主要採用兩種不同的方法研究可規模化大面積製備石墨烯的成長，分別為連續式電漿化學氣相沉積(Roll to roll plasma-enhanced chemical vapor deposition, R2R-PECVD)以及批量式化學氣相沉積(Batch to batch chemical vapor deposition, B2B-CVD)，在R2RCVD的部分，藉由調整不同的氬氣、氫氣、甲烷比例，溫度、電漿功率、成長時間，尋找最佳化參數已達成連續式的成長以及機制的探討。此外，B2BCVD的部分，為了能在有限的腔體內，單批次成長大面積石墨烯，將銅箔以繞捲的方式成長，並放入支架或隔絕層，避免銅箔因高溫而黏合，支架材料為石英，隔離層為氧化鋁及碳布，探討成長石墨烯品質差異與機制探討。PECVD因氫氣蝕刻影響，只有破碎的石墨烯片層，增加柵狀過濾器能有效降低缺陷，缺陷密度從8.77×1012 cm-2降至3.3×1012 cm-2，降低幅度約為60%，但依舊是破碎片層，無法成長連續石墨烯薄膜，而利用碳布繞捲成長的方法，可以得到面積5cm×100cm的大面積石墨烯，晶格大小約為20 μm，其平均片電阻達750 Ω/sq，ID/IG比為0.3，I2D/IG比為0.9，缺陷密度2.43×1012 cm-2，載子遷移率1000 cm2V-1s-1。;Graphene, a single graphite film with only one atomic layer thickness (0.34 nm), has excellent properties such as electron mobility (200,000 cm2V-1s-1), mechanical strength (1,100 GPa), the optical transmittance (> 97 %), chemical stability, high bending strength. It can not only be used in wearable devices but also be applied in photovoltaic panels to increase its stability. Thus, graphene has been considered as one of the promising materials to replace ITO (Indium Tin Oxide) in the future.
Chemical Vapor Deposition (CVD) is a mainstream method for growing graphene thin films on a transition metal substrate. By using this method, we can make large area and high uniformity graphene. However, the high cost limits its application for industrialization. In this experiment, we develop two methods, Roll to roll plasma-enhanced chemical vapor deposition (R2R-PECVD) and Batch to batch chemical vapor deposition (B2B-CVD) to reduce the cost to facilitate the industrialized production. In R2RCVD, different gas flow rate, temperature, plasma strength, and time have been considered to find the optimized condition for continuous growth. About B2B-CVD, to grow large-scale graphene in limited furnace tube. Rolling the copper foil and inserting quartz and carbon cloth, and aluminum oxide to prevent copper foil adhesion in high temperature.The quatz is used as scaffold. For carbon cloth and aluminum oxide, they were used as intercalation material. About PECVD, we couldn’t get continuous graphene because of the hydrogen etching effect. Although we can decrease the defect density from 8.77×1012 cm-2 to 3.33×1012 cm-2 by installing filter. The decreasing rate is approximate 60%, but graphene film is not continuous. By using B2B-CVD (carbon cloth as intercalation material), a large-area graphene with an area of 5×100 cm2 was obtained, damain size about 20 μm, sheet resistance only 750 Ω / sq, ID/IG radio 0.3, I2D/IG radio 0.9, defect density 2.43×1012 cm-2,and its charge carrier mobility ~1000 cm2V-1s-1. |
