Interaction, growth, and ordering of epitaxial graphene on SiC{0001} surfaces: A comparative photoelectron spectroscopy study
Interaction, growth, and ordering of epitaxial graphene on SiC{0001} surfaces: A comparative photoelectron spectroscopy study
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DOI：
10.1103/physrevb.77.155303
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发表时间：
2008-04-01
影响因子：
3.7
通讯作者：
Riley, J. D.
中科院分区：
文献类型：
--
作者：
Emtsev, K. V.;Speck, F.;Riley, J. D.
研究了热诱导生长石墨烯在6 H-SiC两个极性表面上的生长过程，重点研究了生长的初始阶段和界面结构。所采用的实验方法是角分辨价带光电子能谱，软x射线诱导芯能级谱，和低能电子衍射。在Si封端的（0001）表面上，（6根3x 6根3）R30度重构是石墨烯生长的前体，并且其在少层石墨烯（FLG）生长时持续在界面处。（6根3x 6根3）R30度结构是具有共价键合到衬底的石墨烯样原子排列的碳层，其中它负责SiC（0001）上的FLG的方位角排序。相比之下，石墨烯和C-封端的（棒上的000（1））表面之间的相互作用弱得多，这解释了该表面上的FLG的低有序度。开发了SiC{0001}上FLG生长的模型，其中每个新的石墨烯层形成在现有堆叠的底部而不是其顶部。这个模型的产量，结合界面结合强度的差异，一个自然的解释为FLG在两个表面上观察到的不同程度的方位角顺序。
Thermally induced growth of graphene on the two polar surfaces of 6H-SiC is investigated with emphasis on the initial stages of growth and interface structure. The experimental methods employed are angle-resolved valence band photoelectron spectroscopy, soft x-ray induced core-level spectroscopy, and low-energy electron diffraction. On the Si-terminated (0001) surface, the (6 root 3x6 root 3)R30 degrees reconstruction is the precursor of the growth of graphene and it persists at the interface upon the growth of few layer graphene (FLG). The (6 root 3x6 root 3)R30 degrees structure is a carbon layer with graphene-like atomic arrangement covalently bonded to the substrate where it is responsible for the azimuthal ordering of FLG on SiC(0001). In contrast, the interaction between graphene and the C-terminated (000 (1) over bar) surface is much weaker, which accounts for the low degree of order of FLG on this surface. A model for the growth of FLG on SiC{0001} is developed, wherein each new graphene layer is formed at the bottom of the existing stack rather than on its top. This model yields, in conjunction with the differences in the interfacial bonding strength, a natural explanation for the different degrees of azimuthal order observed for FLG on the two surfaces.