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Title: Decoupling of epitaxial graphene via gold intercalation probed by dispersive Raman spectroscopy

Signatures of a superlattice structure composed of a quasi periodic arrangement of atomic gold clusters below an epitaxied graphene (EG) layer are examined using dispersive Raman spectroscopy. The gold-graphene system exhibits a laser excitation energy dependant red shift of the 2D mode as compared to pristine epitaxial graphene. The phonon dispersions in both the systems are mapped using the experimentally observed Raman signatures and a third-nearest neighbour tight binding electronic band structure model. Our results reveal that the observed excitation dependent Raman red shift in gold EG primarily arise from the modifications of the phonon dispersion in gold-graphene and shows that the extent of decoupling of graphene from the underlying SiC substrate can be monitored from the dispersive nature of the Raman 2D modes. The intercalated gold atoms restore the phonon band structure of epitaxial graphene towards free standing graphene.
Authors:
;  [1] ; ;  [2] ; ;  [3] ;  [4] ;  [5]
  1. Semiconductor Materials and Device Group, Electronic and Electrical Engineering, University of Sheffield, Mappin Street, S1 3JD Sheffield (United Kingdom)
  2. Department of Physics, Freie Universit├Ąt Berlin, Arnimallee 14, 14195 Berlin (Germany)
  3. Renishaw, Old Town, Wotton-under-Edge, GL12 7DW Gloucestershire (United Kingdom)
  4. Department of Materials Science and Engineering, Sir Robert Hadfield Building, Mappin Street, S1 3JD Sheffield (United Kingdom)
  5. (Czech Republic)
Publication Date:
OSTI Identifier:
22410171
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 117; Journal Issue: 18; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CLATHRATES; COMPARATIVE EVALUATIONS; DECOUPLING; EPITAXY; EXCITATION; GOLD; GRAPHENE; LASER RADIATION; LAYERS; PHONONS; PROBES; RAMAN SPECTROSCOPY; RED SHIFT; SILICON CARBIDES; SUBSTRATES; SUPERLATTICES