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  • 學位論文

探討銅箔前處理與轉印過程對石墨烯品質影響之研究

Influence of Copper Pretreatment and Transfer Process on the Quality of Graphene

指導教授 : 謝雅萍 王欽戊
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摘要


石墨烯由單顆碳原子厚度以蜂窩狀晶格排列的二維薄膜,目前大家注視的地方在於生長高品質的石墨烯及石墨烯元件,目前在化學氣相沉積法生長的石墨烯的均勻度與覆蓋率會是的主要的問題,到目前為止只能有限的控制這兩個參數。銅箔的形貌將會是個重要因素在石墨烯生長的品質上。由於銅箔表面覆蓋一層氧化鉻的抗氧化層,及本身的氧化物,將會影響石墨烯生長,所以使用前處理過程將銅表面的氧化物給去除,在前處理方法之中電解拋光是最好的方法,電解拋光不只能去除表面的氧化金屬還能達到表面平坦的效果。 在我的研究中,發現銅箔粗糙度(包含表面粒子密度及粒子高度)會造成石墨烯電性下降,透過最佳電解拋光銅箔處理結果,將表面的粗糙度從 90 nm下降至 30 nm,表面粒子密度從 1.2 %下降至 0.75 %,表面粒子高度維持在 150 nm左右,而能得到最高覆蓋及品質的石墨烯。再透過轉印參數的選取,控制PMMA濃度、烘烤PMMA溫度、蝕刻液的種類、浸泡丙酮時間及溫度等…,而達到乾淨、無裂痕的轉印結果。 透過電解拋光銅箔及轉印步驟參數的控制後,可以得到較高品質的石墨烯,石墨烯超過 95 %的石墨烯覆蓋率, mobility提升了41%、載子濃度維持在 2-3×10^12 /cm^2左右,相信這樣的結果對日後實驗室在開發石墨烯原件上有很大的幫助。

並列摘要


Graphene is a one-atom-thick planar sheets of carbon atoms that are arranged in a honeycomb crystal lattice. The strong interest in graphene has motivated the scalable production of high-quality graphene and graphene devices. The uniform coverage of CVD-grown graphene is still a critical issue and reports to date have shown only limited success in controlling this parameter. Surface morphology of the catalytic Cu substrate was found to be a crucial factor in determining the quality of the graphene film. The Cu foils are typically covered with a layer of chromium oxide for anticorrosion protection and native Cu oxide, so that will affect graphene growth. Among these pretreatment methods electropolishing is the best way to overcome the problem. Electropolishing treatment not only removes the metal oxide but make the copper surface flat. In my study, I found the roughness of Cu surface (consist of particles density and mean grain size of particles) will affect graphene quality in electrical measurement results. Using the best results of electropolishing pretreatment will reduce the roughness of copper surface from 90 nm to 30 nm, the particles density from 1.2 % to 0.75 %, and keep the mean grain size of particles at ~150 nm. Graphene grown on electropolished copper can get the high coverage and quality of graphene. According to experiment of tune the concentration of PMMA, PMMA baking temperature, etching type, acetone dipping time and temperature, etc., we choose the best parameters of transfer procedure and get the clean and crackless transfer of graphene. I combine the pretreatment results with transfer results, and get the high quality graphene with a 41% increased mobility and a very low doping concentration of 2-3×10^12 /cm^2. I think these results are useful to develop the graphene device in the future.

參考文獻


Pei.; and Yong P. Chen.
55. Lee, W. H.; Suk, J. W.; Lee, J.; Hao, Y.; Park, J.; Yang, J. W.; Ha, H.-W.; Murali, S.;
30. Kim, E. S.; Shin, H.-J.; Yoon, S.-M.; Han, G. H.; Chae, S. J.; Bae, J. J.; Gunes, F.;
40. Han, G. H.; Gunes, F.; Bae, J. J.; Kim, E. S.; Chae, S. J.; Shin, H. J.; Choi, J. Y.; Pribat,
10. Zhang, D.; Choy, W. C. H.; Wang, C. C. D.; Li, X.; Fan, L. L.; Wang, K. L.; Zhu, H. W.

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