Atomic-Scale Evidence for Potential Barriers and Strong Carrier Scattering at Graphene Grain Boundaries: A Scanning Tunneling Microscopy Study

We use scanning tunneling microscopy and spectroscopy to examine the electronic nature of grain boundaries (GBs) in polycrystalline graphene grown by chemical vapor deposition (CVD) on Cu foil and transferred to SiO2 substrates. We find no preferential orientation angle between grains, and the GBs a...

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Bibliographic Details
Published in:ACS nano 2013-01, Vol.7 (1), p.75-86
Main Authors: Koepke, Justin C, Wood, Joshua D, Estrada, David, Ong, Zhun-Yong, He, Kevin T, Pop, Eric, Lyding, Joseph W
Format: Article
Language:English
Subjects:
Chemical vapor deposition
Electron Transport
Electronics
Grain boundaries
Graphene
Graphite - chemistry
Materials Testing
Microscopy, Scanning Tunneling - methods
Molecular Conformation
Nanostructure
Nanostructures - chemistry
Nanostructures - ultrastructure
Particle Size
Scanning tunneling microscopy
Scattering
Silicon dioxide
Surface Properties
Wave propagation
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Summary:We use scanning tunneling microscopy and spectroscopy to examine the electronic nature of grain boundaries (GBs) in polycrystalline graphene grown by chemical vapor deposition (CVD) on Cu foil and transferred to SiO2 substrates. We find no preferential orientation angle between grains, and the GBs are continuous across graphene wrinkles and SiO2 topography. Scanning tunneling spectroscopy shows enhanced empty states tunneling conductance for most of the GBs and a shift toward more n-type behavior compared to the bulk of the graphene. We also observe standing wave patterns adjacent to GBs propagating in a zigzag direction with a decay length of ∼1 nm. Fourier analysis of these patterns indicates that backscattering and intervalley scattering are the dominant mechanisms responsible for the mobility reduction in the presence of GBs in CVD-grown graphene.
ISSN:1936-0851
1936-086X
DOI:10.1021/nn302064p