Formation of graphene atop a Si adlayer on the C-face of SiC

Research output: Contribution to journalArticleScientificpeer-review

Researchers

  • Jun Li
  • Qingxiao Wang
  • Guowei He
  • Michael Widom
  • Lydia Nemec
  • Volker Blum
  • Moon Kim
  • Patrick Rinke

  • Randall M. Feenstra

Research units

  • Fritz-Haber-Institut der Max-Planck-Gesellschaft
  • Duke University
  • Carnegie Mellon University
  • University of Texas Dallas
  • Carnegie Mellon Univ, Carnegie Mellon University, Dept Phys
  • Univ Texas Dallas, University of Texas System, University of Texas Dallas, Dept Mat Sci & Engn

Abstract

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.

Details

Original languageEnglish
Article number084006
Pages (from-to)1-12
Number of pages12
JournalPhysical Review Materials
Volume3
Issue number8
Publication statusPublished - 19 Aug 2019
MoE publication typeA1 Journal article-refereed

    Research areas

  • SURFACE RECONSTRUCTIONS, EPITAXIAL GRAPHENE, MOLECULAR-DYNAMICS, GAN(0001)

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