Improving Terahertz Sheet Conductivity of Graphene Films Synthesized by Atmospheric Pressure Chemical Vapor Deposition with Acetylene

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• 作者：Mei Qi ; Yixuan Zhou ; Fangrong Hu ; Xinlong Xu ; Weilong Li ; Anran Li ; Jintao Bai ; Zhaoyu Ren
• 刊名：Journal of Physical Chemistry C
• 出版年：2014
• 出版时间：July 10, 2014
• 年：2014
• 卷：118
• 期：27
• 页码：15054-15060
• 全文大小：341K
• ISSN：1932-7455

文摘

Graphene has shown great potential for terahertz (THz) applications in recent years. THz sheet conductivity of graphene is essential to assess the high performance of THz devices such as modulators based on graphene. In this work, THz sheet conductivity of graphene grown with different temperatures, along with the effects of chemical doping by HNO₃, were studied in detail. Graphene films were synthesized on Cu surface by atmospheric pressure chemical vapor deposition with C₂H₂. Different samples with growth temperature from 850 to 1030 掳C were characterized by Raman spectroscopy, transmission electron microscope, and UV鈥搗is spectroscopy. THz time-domain spectroscopy was used to study the THz sheet conductivity of the samples before and after HNO₃ doping. The results show that graphene grown at 1000 掳C has the highest THz sheet conductivity. As compared to the sample grown at 850 掳C, the value enhances 600%. In addition, after HNO₃ doping, the THz sheet conductivity of the sample grown at 1000 掳C becomes 2.42 mS, which enhances 44%. These indicate that both the optimization of the growth temperature and chemical doping can improve the THz sheet conductivity of graphene significantly. Combining with the characterization of the material, we have attributed the effect of the growth temperature to the influence of carrier momentum scattering time in graphene, and the chemical doping to the influence of the carrier concentration in graphene. This work advances the understanding of improving THz sheet conductivity by in situ growth and postgrowth and paves the way for efficient THz components with graphene.