• 文献标题:   Formation of graphene atop a Si adlayer on the C-face of SiC
  • 文献类型:   Article
  • 作  者:   LI J, WANG QX, HE GW, WIDOM M, NEMEC L, BLUM V, KIM M, RINKE P, FEENSTRA RM
  • 作者关键词:  
  • 出版物名称:   PHYSICAL REVIEW MATERIALS
  • ISSN:   2475-9953
  • 通讯作者地址:   Carnegie Mellon Univ
  • 被引频次:   0
  • DOI:   10.1103/PhysRevMaterials.3.084006
  • 出版年:   2019

▎ 摘  要

The structure of the SiC(000 (1) over bar) surface, the C-face of the {0001} SiC surfaces, is studied as a function of temperature and of pressure in a gaseous environment of disilane (Si2H6). Various surface reconstructions are observed, both with and without the presence of an overlying graphene layer (which spontaneously forms at sufficiently high temperatures). Based on cross-sectional scanning transmission electron microscopy measurements, the interface structure that forms in the presence of the graphene is found to contain 1.4-1.7 monolayers (ML) of Si, a somewhat counter-intuitive result since, when the graphene forms, the system is actually under C-rich conditions. Using ab initio thermodynamics, it is demonstrated that there exists a class of Si-rich surfaces containing about 1.3 ML of Si that are stable on the surface (even under C-rich conditions) at temperatures above similar to 400 K. The structures that thus form consist of Si adatoms atop a Si adlayer on the C-face of SiC, with or without the presence of overlying graphene.