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Effects of a Plasma Generated from a Gas Mixture of Nitrogen, Methane, and Hydrogen on the Reduction of Graphene-Oxide Thin Films
New Phys.: Sae Mulli 2018; 68: 318~323
Published online March 30, 2018;
© 2018 New Physics: Sae Mulli.

Sung-Youp LEE, Hong Tak KIM, Dong Hun KEE, Jung Su PARK, Hyeong-Rag LEE*

Department of Physics, Kyungpook National University, Daegu 41566, Korea
Correspondence to:
Received December 15, 2017; Revised February 5, 2018; Accepted February 6, 2018.
cc This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License ( which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
In this study, reduced-graphene-oxide (r-GO) thin films were fabricated using the plasma reduction method, and their physical properties were evaluated. The plasma was generated from a gas mixture of N$_2$, CH$_4$, and H$_2$ by using a radio-frequency (rf) power source (13.56 MHz). The GO films were treated in both the bulk plasma region ($R_b$) and the sheath region ($R_s$). When exposed to the plasma, the GO films were rapidly reduced, and their surfaces changed from hydrophilic to hydrophobic. Untill 5 min, the optical transmittances in both regions were over 85% for visible light and over 95% for infrared light. After 5 min, the optical transmittance of the r-GO film kept decreasing in the $R_b$ while its optical transmittance remained constant in the $R_s$. The sheet resistance of the r-GO film in the Rb continuously decreased while the sheet resistance increased in the $R_s$. These results originate from the differences between the $R_b$ and the $R_s$: chemical reactions were dominant in the $R_b$ whereas physical reactions were dominant in the $R_s$.
PACS numbers: 81.05.ue, 81.15.-z, 52.77.-j
Keywords: Plasma reduction, Graphene, Reduced graphene oxide

July 2018, 68 (7)
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