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Title: Voltage contrast X-ray photoelectron spectroscopy reveals graphene-substrate interaction in graphene devices fabricated on the C- and Si- faces of SiC

We report on an X-ray photoelectron spectroscopy (XPS) study of two graphene based devices that were analyzed by imposing a significant current under +3 V bias. The devices were fabricated as graphene layers(s) on hexagonal SiC substrates, either on the C- or Si-terminated faces. Position dependent potential distributions (IR-drop), as measured by variations in the binding energy of a C1s peak are observed to be sporadic for the C-face graphene sample, but very smooth for the Si-face one, although the latter is less conductive. We attribute these sporadic variations in the C-face device to the incomplete electrical decoupling between the graphene layer(s) with the underlying buffer and/or substrate layers. Variations in the Si2p and O1s peaks of the underlayer(s) shed further light into the electrical interaction between graphene and other layers. Since the potential variations are amplified only under applied bias (voltage-contrast), our methodology gives unique, chemically specific electrical information that is difficult to obtain by other techniques.
Authors:
;  [1] ; ; ;  [2] ;  [3]
  1. Department of Chemistry, Bilkent University, 06800 Ankara (Turkey)
  2. Department of Physics, Bilkent University, 06800 Ankara (Turkey)
  3. Institute of Electronic Materials Technology, Wolczynska 133, 01-919 Warsaw (Poland)
Publication Date:
OSTI Identifier:
22482116
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 107; Journal Issue: 12; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; BINDING ENERGY; ELECTRIC POTENTIAL; GRAPHENE; INTERACTIONS; LAYERS; SILICON CARBIDES; SUBSTRATES; X-RAY PHOTOELECTRON SPECTROSCOPY