Nucleation of Graphene Layers on Magnetic Oxides: Co3O4(111) and Cr2O3(0001) from Theory and Experiment

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• 作者：John Beatty ; Tao ChengYuan Cao ; M. Sky Driver ; William A. Goddard III ; Jeffry A. Kelber
• 刊名：The Journal of Physical Chemistry Letters
• 出版年：2017
• 出版时间：January 5, 2017
• 年：2017
• 卷：8
• 期：1
• 页码：188-192
• 全文大小：392K
• ISSN：1948-7185

文摘

We report directly grown strongly adherent graphene on Co₃O₄(111) by carbon molecular beam epitaxy (C MBE) at 850 K and density functional theory (DFT) findings that the first graphene layer is reconstructed to fit the Co₃O₄ surface, while subsequent layers retain normal graphene structure. This adherence to the Co₃O₄ structure results from partial bonding of half the carbons to top oxygens of the substrate. This structure is validated by X-ray photoelectron spectroscopy and low-energy electron diffraction studies, showing layer-by-layer graphene growth with ∼0.08 electrons/carbon atom transferred to the oxide from the first graphene layer, in agreement with DFT. In contrast, for Cr₂O₃ DFT finds no strong bonding to the surface and C MBE on Cr₂O₃(0001) yields only graphite formation at 700 K, with C desorption above 800 K. Thus strong graphene-to-oxide charge transfer aids nucleation of graphene on incommensurate oxide substrates and may have implications for spintronics.