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

Date
2015
Advisor
Instructor
Source Title
Applied Physics Letters
Print ISSN
0003-6951
Electronic ISSN
1077-3118
Publisher
American Institute of Physics Inc.
Volume
107
Issue
12
Pages
121603-1 - 121603-5
Language
English
Type
Article
Journal Title
Journal ISSN
Volume Title
Abstract

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.

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Keywords
Bias voltage, Binding energy, Graphene, Photoelectrons, Photons, Silicon, Silicon carbide, Substrates, Voltage measurement, Electrical decoupling, Electrical interaction, Graphene substrates, Position dependents, Potential distributions, Potential variations, Substrate layers, X-ray photoelectron spectroscopy studies, X ray photoelectron spectroscopy
Citation
Published Version (Please cite this version)
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