不同极性6H-SiC表面石墨烯的制备及其电子结构的研究

Preparation of graphene on different-polarity 6H-SiC substrates and the study of their electronic structures

在超高真空设备中,采用高温退火的方法在6H-SiC两个极性面(0001)和(0001-)面(即Si面和C面)外延石墨烯(EG).利用低能电子衍射(LEED)和同步辐射光电子能谱(SRPES)对样品的生长过程进行了原位研究,而后利用激光拉曼光谱(Raman)和近边X射线吸收精细结构(XANES)等实验技术对制备的样品进行了表征.结果表明我们在两种极性面均制备出了质量较好的石墨烯样品.而有关两种石墨烯的对比性研究发现:Si面EG呈同一取向而C面EG呈各向异性;Si面EG与衬底存在类似于金刚石C—sp3键的界面相互作用,受到衬底的影响较大,而C面EG与衬底的相互作用较弱,受到衬底的影响较小.

The epitaxial graphene（EG） layers are grown on Si-terminated 6H-SiC（0001） substrates and C-terminated 6H-SiC（0001-） substrates separately by thermal annealing in an ultrahigh vacuum chamber.Low energy electron diffraction（LEED） and synchrotron radiation photoelectron spectroscopy（SRPES） are used to in-situ study the synthesis process,and the prepared samples are characterized by Raman spectrum,and near edge X-ray absorption fine structure（XANEX）.The results show that we have successfully prepared high-quality EG layers on the two polar surfaces of 6H-SiC.The comparisons studies indicate that Si terminated EG is highly oriented while C terminated EG is anisotropic,and that the interface interaction similar to that of C-sp3 bond of diamond exists on the Si terminated EG,the interaction between the epitaxial film and substrate is stronger,while on the C terminated EG there is no such interaction,and the interaction between the epitaxial film and substrate is weaker.