Chemical vapor deposition of high quality graphene films from carbon dioxide atmospheres.
Chemical vapor deposition of high quality graphene films from carbon dioxide atmospheres.
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DOI：
10.1021/nn504822m
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发表时间：
2015-01
期刊：
影响因子：
17.1
通讯作者：
A. Strudwick;N. Weber;M. Schwab;Michel Kettner;R. Weitz;J. Wünsch;K. Müllen;H. Sachdev
中科院分区：
文献类型：
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作者：
A. Strudwick;N. Weber;M. Schwab;Michel Kettner;R. Weitz;J. Wünsch;K. Müllen;H. Sachdev
基于石墨烯的下一代电子应用的实现本质上取决于通过化学气相沉积（CVD）大规模生产石墨烯薄膜。我们展示了如何通过使用二氧化碳和富含二氧化碳的气体气氛来改善铜金属基板的均匀性和同质性以及生长化学等关键挑战。我们的方法能够实现不含元素氢的石墨烯薄膜生产方案，并提供与传统基于氢/甲烷的 CVD 工艺生产的样品相比质量优异的石墨烯层。通过扫描电子显微镜 (SEM)、能量色散 X 射线光谱 (EDX) 和拉曼显微镜、薄层电阻和传输测量对基材和所得石墨烯薄膜进行表征。拉曼图显示了铜上生长的石墨烯薄膜的卓越品质，显示在 514.5 nm 激发下平均 G 带宽度低至 18 ± 8 cm(-1)。此外，在基于二氧化碳的生长方案获得的转移膜中，观察到电子的电荷载流子迁移率高达 1975 cm(2)/(V s)。石墨烯薄膜质量的提高可以通过二氧化碳的温和氧化特性来解释，二氧化碳在高温下可以通过有效去除预先存在和新出现的碳杂质以及连续抑制和原位蚀刻CVD生长过程中共沉积的质量较低的碳来均匀调节基材。
The realization of graphene-based, next-generation electronic applications essentially depends on a reproducible, large-scale production of graphene films via chemical vapor deposition (CVD). We demonstrate how key challenges such as uniformity and homogeneity of the copper metal substrate as well as the growth chemistry can be improved by the use of carbon dioxide and carbon dioxide enriched gas atmospheres. Our approach enables graphene film production protocols free of elemental hydrogen and provides graphene layers of superior quality compared to samples produced by conventional hydrogen/methane based CVD processes. The substrates and resulting graphene films were characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and Raman microscopy, sheet resistance and transport measurements. The superior quality of the as-grown graphene films on copper is indicated by Raman maps revealing average G band widths as low as 18 ± 8 cm(-1) at 514.5 nm excitation. In addition, high charge carrier mobilities of up to 1975 cm(2)/(V s) were observed for electrons in transferred films obtained from a carbon dioxide based growth protocol. The enhanced graphene film quality can be explained by the mild oxidation properties of carbon dioxide, which at high temperatures enables an uniform conditioning of the substrates by an efficient removal of pre-existing and emerging carbon impurities and a continuous suppression and in situ etching of carbon of lesser quality being co-deposited during the CVD growth.