Epitaxial Chemical Vapor Deposition Growth of Single-Layer Graphene over Cobalt Film Crystallized on Sapphire
Epitaxial Chemical Vapor Deposition Growth of Single-Layer Graphene over Cobalt Film Crystallized on Sapphire
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DOI：
10.1021/nn102519b
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发表时间：
2010-12-01
期刊：
影响因子：
17.1
通讯作者：
Mizuno, Seigi
中科院分区：
文献类型：
--
作者：
Ago, Hiroki;Ito, Yoshito;Mizuno, Seigi
采用外延化学气相沉积(CVD)方法在c面蓝宝石晶化的Co薄膜上生长了均匀的单层石墨烯。通过优化的高温溅射和连续的氢-2退火，在蓝宝石衬底上实现了单晶Co薄膜。这种晶态Co膜可以形成均匀的单层石墨烯，而在SiO_2/Si衬底上沉积的多晶Co膜可以形成许多不同厚度的石墨烯薄片。当合成温度为1000℃时，石墨烯和Co晶格之间存在外延关系，单层石墨烯的六方晶格方向与底层Co/蓝宝石衬底的方向完全一致。石墨烯的取向取决于生长温度，在900℃时，石墨烯晶格相对于Co晶格方向旋转22+/-8度。我们的工作拓展了在各种金属催化剂上合成单层石墨烯的可能性。此外，我们的CVD生长提供了具有预定取向的石墨烯薄膜，因此可以应用于石墨烯工程，例如沿着特定的晶体方向切割，以用于未来的电子应用。
Epitaxial chemical vapor deposition (CVD) growth of uniform single-layer graphene is demonstrated over Co film crystallized on c-plane sapphire. The single crystalline Co film is realized on the sapphire substrate by optimized high-temperature sputtering and successive H-2 annealing. This crystalline Co film enables the formation of uniform single-layer graphene, while a polycrystalline Co film deposited on a SiO2/Si substrate gives a number of graphene flakes with various thicknesses. Moreover, an epitaxial relationship between the as-grown graphene and Co lattice is observed when synthesis occurs at 1000 degrees C; the direction of the hexagonal lattice of the single-layer graphene completely matches with that of the underneath Co/sapphire substrate. The orientation of graphene depends on the growth temperature and, at 900 degrees C, the graphene lattice is rotated at 22 +/- 8 degrees with respect to the Co lattice direction. Our work expands a possibility of synthesizing single-layer graphene over various metal catalysts. Moreover, our CVD growth gives a graphene film with predefined orientation, and thus can be applied to graphene engineering, such as cutting along a specific crystallographic direction, for future electronics applications.