Direct imaging of charged impurity density in common graphene substrates

Kristen M. Burson; William G. Cullen; Shaffique Adam; Cory R. Dean; K. Watanabe; T. Taniguchi; Philip Kim; Michael S. Fuhrer

doi:10.1021/nl4012529

Direct imaging of charged impurity density in common graphene substrates

Kristen M. Burson, William G. Cullen, Shaffique Adam, Cory R. Dean, K. Watanabe, T. Taniguchi, Philip Kim, Michael S. Fuhrer

Department of Physics

Research output: Contribution to journal › Article › peer-review

76 Scopus citations

Abstract

Kelvin probe microscopy in ultrahigh vacuum is used to image the local electrostatic potential fluctuations above hexagonal boron nitride (h-BN) and SiO₂, common substrates for graphene. Results are compared to a model of randomly distributed charges in a two-dimensional (2D) plane. For SiO ₂, the results are well modeled by 2D charge densities ranging from 0.24 to 2.7 × 10¹¹ cm^-2, while h-BN displays potential fluctuations 1-2 orders of magnitude lower than SiO₂, consistent with the improvement in charge carrier mobility for graphene on h-BN compared to SiO₂. Electron beam exposure of SiO₂ increases the charge density fluctuations, creating long-lived metastable charge populations of ∼2 × 10¹¹ cm^-2 at room temperature, which can be reversed by heating.

Original language	English
Pages (from-to)	3576-3580
Number of pages	5
Journal	Nano Letters
Volume	13
Issue number	8
DOIs	https://doi.org/10.1021/nl4012529
State	Published - Aug 14 2013

Keywords

charge inhomogeneity
charged impurity scattering
Graphene
Kelvin probe force microscopy
noncontact atomic force microscopy

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10.1021/nl4012529

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title = "Direct imaging of charged impurity density in common graphene substrates",

abstract = "Kelvin probe microscopy in ultrahigh vacuum is used to image the local electrostatic potential fluctuations above hexagonal boron nitride (h-BN) and SiO2, common substrates for graphene. Results are compared to a model of randomly distributed charges in a two-dimensional (2D) plane. For SiO 2, the results are well modeled by 2D charge densities ranging from 0.24 to 2.7 × 1011 cm-2, while h-BN displays potential fluctuations 1-2 orders of magnitude lower than SiO2, consistent with the improvement in charge carrier mobility for graphene on h-BN compared to SiO2. Electron beam exposure of SiO2 increases the charge density fluctuations, creating long-lived metastable charge populations of ∼2 × 1011 cm-2 at room temperature, which can be reversed by heating.",

keywords = "charge inhomogeneity, charged impurity scattering, Graphene, Kelvin probe force microscopy, noncontact atomic force microscopy",

author = "Burson, \{Kristen M.\} and Cullen, \{William G.\} and Shaffique Adam and Dean, \{Cory R.\} and K. Watanabe and T. Taniguchi and Philip Kim and Fuhrer, \{Michael S.\}",

year = "2013",

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doi = "10.1021/nl4012529",

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journal = "Nano Letters",

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TY - JOUR

T1 - Direct imaging of charged impurity density in common graphene substrates

AU - Burson, Kristen M.

AU - Cullen, William G.

AU - Adam, Shaffique

AU - Dean, Cory R.

AU - Watanabe, K.

AU - Taniguchi, T.

AU - Kim, Philip

AU - Fuhrer, Michael S.

PY - 2013/8/14

Y1 - 2013/8/14

N2 - Kelvin probe microscopy in ultrahigh vacuum is used to image the local electrostatic potential fluctuations above hexagonal boron nitride (h-BN) and SiO2, common substrates for graphene. Results are compared to a model of randomly distributed charges in a two-dimensional (2D) plane. For SiO 2, the results are well modeled by 2D charge densities ranging from 0.24 to 2.7 × 1011 cm-2, while h-BN displays potential fluctuations 1-2 orders of magnitude lower than SiO2, consistent with the improvement in charge carrier mobility for graphene on h-BN compared to SiO2. Electron beam exposure of SiO2 increases the charge density fluctuations, creating long-lived metastable charge populations of ∼2 × 1011 cm-2 at room temperature, which can be reversed by heating.

AB - Kelvin probe microscopy in ultrahigh vacuum is used to image the local electrostatic potential fluctuations above hexagonal boron nitride (h-BN) and SiO2, common substrates for graphene. Results are compared to a model of randomly distributed charges in a two-dimensional (2D) plane. For SiO 2, the results are well modeled by 2D charge densities ranging from 0.24 to 2.7 × 1011 cm-2, while h-BN displays potential fluctuations 1-2 orders of magnitude lower than SiO2, consistent with the improvement in charge carrier mobility for graphene on h-BN compared to SiO2. Electron beam exposure of SiO2 increases the charge density fluctuations, creating long-lived metastable charge populations of ∼2 × 1011 cm-2 at room temperature, which can be reversed by heating.

KW - charge inhomogeneity

KW - charged impurity scattering

KW - Graphene

KW - Kelvin probe force microscopy

KW - noncontact atomic force microscopy

UR - https://www.scopus.com/pages/publications/84881593348

U2 - 10.1021/nl4012529

DO - 10.1021/nl4012529

M3 - Article

AN - SCOPUS:84881593348

SN - 1530-6984

VL - 13

SP - 3576

EP - 3580

JO - Nano Letters

JF - Nano Letters

IS - 8

ER -

Direct imaging of charged impurity density in common graphene substrates

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Keywords

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