課題番号 ：S-16-NI-27
利用形態 ：共同研究
利用課題名（日本語） ：グラフェン層形成のその場TEM観察
Program Title (English) ：Graphene layer formation observed by in situ TEM
利用者名（日本語） ：モハマド ザムリ ユソプ1), モハマド サウフィ ロスミ2), カリタ ゴラプ2), 種村
眞幸2)
Username (English) ：Mohd Zamri Yusop1), Mohamad Saufi Rosmi2), Golap Kalita2) and Masaki
Tanemura2)
所属名（日本語） ：1) マレーシア工科大 機械工学科, 2) 名古屋工業大学 物理工学工学専攻
Affiliation (English) ：1) Department of Materials, Manufacturing and Industrial Engineering, Faculty
of Mechanical Engineering, Universiti Teknologi Malaysia, 2) Department of
Physical Science and Engineering, Nagoya Institute of Technology.

１．概要（Summary ）
The formation of graphene from a single copper–carbon nanoneedle (Cu–CNN) during the measurement of current–voltage (I–V) was observed using in situ transmission electron microscopy (TEM). As grown Cu-CNN was characterized by Cu nanoparticles dispersed in amorphous C nanoneedle. Under a high current flow in TEM, the Cu nanoparticles melted and evaporated due to Joule heating. The amorphous carbon began crystallizing and transformed into sp2 graphitic carbon, which was catalyzed by the dispersed Cu nanoparticles, resulting in the graphene nanowire consisting of agglomerated graphene flakes.

２．実験（Experimental）
The copper foils were bombarded by Ar+ ions at the incidence angle of 45o for 60 minutes with the simultaneous carbon supply using a room temperature carbon nanofiber (CNF) synthesis system. Then the samples thus prepared were mounted on a special sample holder without any post treatment for the in situ TEM experiment (JEOL JEM-2010). The interaction of carbon atoms on the metal atoms were carefully observed during the in situ TEM experiment.

３．結果と考察（Results and Discussion）
Figure 1 and 2 show I-V curve and the graphene formation process during the I-V measurement for a Cu-CNN, respectively, disclosing the transformation from the amorphous carbon structure to agglomerated graphene flaks (about 3 layers in average thickness) catalysed by the dispersed Cu nanoparticles and the evaporation of Cu after the steep increase in current [1]. Compared with Cu coated CNFs [2], formation temperature of graphene as low as 750oC was achieved for the Cu-CNN, due to the reduction in melting point induced by the size effect of Cu nanoparticles dispersed in the Cu-CNN. After the formation of graphene nanowire of about 800 nm in length and 50-100 nm in diameter, current density as high as 106 A/cm2 was achieved.

Fig. 1 I-V curve of a Cu-CNN

Fig. 2 (a)-(e) A series of TEM images taken during I-V measurement for a Cu-CNN, disclosing the formation process of a graphene nanowire. (f) A magnified TEM image of the formed graphene [1].

４．その他・特記事項（Others）
参考文献
[1] Mohamad Saufi Rosmi, Mohd Zamri Mohd Yusop, et al., RSC Advances, 6 (2016) 82459-82466.
[2] Mohamad Saufi Rosmi, Mohd Zamri Mohd Yusop, et al., Scientific Reports, 4 (2014) 7563.

５．論文・学会発表（Publication/Presentation）
(1) Mohamad Saufi Rosmi, Yazid Yaakob, Mohd Zamri Mohd Yusop, Subash Sharma, Ritesh Vishwakarma, Mona Ibrahim Araby, Golap Kalita and Masaki Tanemura, RSC Advances, 6 (2016) 82459-82466.
(2) Mohd Zamri Yusop, Mohamad Saufi Rosmi, Yazid Yaakob, Chisato Takahashi, Subash Sharma, Golap Kalita, and Masaki Tanemura, EMN Meeting on Nanowires 2016, May.16-19(2016), Amsterdam.
(3) Masaki Tanemura, M. S. Rosmi, S. Sharma, G. Kalita, Y. Yaakob, C. Takahashi, M. Z. Yusop, European Conference on Surface Science (ECOSS-32), Aug.28-Sept.2 (2016), Grenoble, France
(4) Masaki Tanemura, M. S. Rosmi, S. Sharma, G. Kalita, Y. Yaakob, C. Takahashi, M. Z. Yusop, 8th International Workshop on Advanced Materials Science and Nanotechnology (IWAMSN 2016), Nov.8-12(2016), Vietram.
(5) Masaki Tanemura, M. S. Rosmi, S. Sharma, G. Kalita, Y. Yaakob, C. Takahashi and M. Z. Yusop, 6th Interdisciplinary Symposium on Materials Chemistry(ISMC2016), Des.6-10 (2016), India.
(6) Mohamad Saufi Rosmi, Mohd Zamri Yusop, Yazid Yaakob, Riteshkumar Vishwakarma1, Golap Kalita and Masaki Tanemura, 8th International Conference on Nanoscience and Nanotechnology 2017 (NANO-SciTech 2017), Feb. 24-27 (2017), Malaysia.
(7) Masaki Tanemura, M. S. Rosmi, S. Sharma, G. Kalita, Y. Yaakob, C. Takahashi and M. Z. Yusop, Graphene 2017, Mar. 28-31 (2017), Barcelona.

６．関連特許（Patent）
なし