在低溫成長高品質氣相沉積石墨烯

Abstract

甲烷與氫氣製作高品質氣相沉積石墨烯通常需要在高於1000℃的溫度才能完成，而若降低成長溫度，石墨烯的品質也將跟著下降。 在此論文，我們發展出通過控制生長參數如，基板表面紋理，初始成核，和降溫過程，在 低溫300℃也可以成 長出高於97%的覆蓋率與高達約 ~2000 cm2/V.sec的載子遷移率的石墨烯氣相沉積方法。利用原子力顯微鏡，光學顯微，顯微拉曼光譜，和載子遷移率測量揭示了上述 生長控制參數的關鍵角色。此外，我們還研究了成長溫度改變對石墨烯生成的影響，我們發現石墨烯的品質隨著溫度的降低而變差，但隨後在溫度 更低時又變好。這個出乎意料的結果表明在CVD石墨烯成長的過程當中，碳的生長和脫附都重要，且彼此之間為競爭的關係。

High quality chemical vapor deposition (CVD) graphene using methane and hydrogen is commonly prepared on Cu foils at a temperature >1000 ℃. However, it is desirable to reduce this growth temperature without sacrificing the quality. We discovered that high quality continuous graphene with a carrier mobility ~2000 cm2/V.sec and a coverage >97% can be prepared down to 300℃, using thermal CVD and only CH4 and H2. This result is enabled by controlling the substrate texture and initial graphene nucleation process. Combined atomic force microscopy, optical microscopy, micro-Raman, and mobility measurement reveal the key roles of these the aforementioned growth control parameters. We also conducted growth temperature dependence and found that graphene quality first deteriorates with decreasing temperature but then recovers. This unexpected result indicates the presence and significance of competing desorption and growth processes during graphene CVD.