Activation Energy Paths for Graphene Nucleation and Growth on Cu
Activation Energy Paths for Graphene Nucleation and Growth on Cu
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DOI：
10.1021/nn3008965
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发表时间：
2012-04-01
期刊：
影响因子：
17.1
通讯作者：
Saiz, Eduardo
中科院分区：
文献类型：
--
作者：
Kim, HoKwon;Mattevi, Cecilia;Saiz, Eduardo
晶片尺寸的单晶石墨烯的合成仍然是其固有性质在电子学中应用的一个挑战。到目前为止，石墨烯的大面积化学气相沉积已经产生了一种多晶材料，其中的晶界对其电学性能是有害的。在这里，我们研究了石墨烯在铜表面的成核和生长动力学的物理化学机制，为晶片级单晶的工程合成提供了新的见解。石墨烯由碳原子物种的过饱和部分结晶而成，其成核密度是碳原子物种的迁移性与其脱附速率竞争的结果。由于这些现象的能量学随着温度的变化而变化，成核激活能可以跨越很大的范围(1-3 eV)，从而合理地预测单个核的尺寸和密度分布。生长限制步骤是碳吸附原子物种附着在石墨烯边缘，这与铜的晶体取向无关。
The synthesis of wafer-scale single crystal graphene remains a challenge toward the utilization of its intrinsic properties In electronics. Until now, the large-area chemical vapor deposition of graphene has yielded a polycrystalline material, where grain boundaries are detrimental to its electrical properties. Here, we study the physicochemical mechanisms underlying the nucleation and growth kinetics of graphene on copper, providing new Insights necessary for the engineering synthesis of wafer-scale single crystals. Graphene arises from the crystallization of a supersaturated fraction of carbon-adatom species, and its nucleation density is the result of competition between the mobility of the carbon-adatom species and their desorption rate. As the energetics of these phenomena varies with temperature, the nucleation activation energies can span over a wide range (1-3 eV) leading to a rational prediction of the individual nuclei size and density distribution. The growth-limiting step was found to be the attachment of carbon-adatom species to the graphene edges, which was Independent of the Cu crystalline orientation.