Abstract
| Original language | English |
|---|---|
| Journal | Nano Research |
| Volume | 10 |
| Issue number | 10 |
| Pages (from-to) | 3596-3605 |
| Number of pages | 10 |
| ISSN | 1998-0124 |
| DOIs | |
| Publication status | Published - 2017 |
Keywords
- CVD graphene
- Doping inhomogeneity
- Electrical measurements
- van der Pauw
- hBN-encapsulated graphene
- Finite element simulations
- Raman mapping
Cite this
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Quality assessment of graphene: Continuity, uniformity, and accuracy of mobility measurements. / Mackenzie, David; Buron, Jonas Christian Due; Whelan, Patrick Rebsdorf; Caridad, Jose; Bjergfelt, Martin; Luo, Birong; Shivayogimath, Abhay; Smitshuysen, Anne Lyck; Thomsen, Joachim Dahl; Booth, Tim ; Gammelgaard, Lene; Zultak, Johanna; Jessen, Bjarke Sørensen; Bøggild, Peter; Petersen, Dirch Hjorth.
In: Nano Research, Vol. 10, No. 10, 2017, p. 3596-3605.Research output: Contribution to journal › Journal article › Research › peer-review
TY - JOUR
T1 - Quality assessment of graphene: Continuity, uniformity, and accuracy of mobility measurements
AU - Mackenzie, David
AU - Buron, Jonas Christian Due
AU - Whelan, Patrick Rebsdorf
AU - Caridad, Jose
AU - Bjergfelt, Martin
AU - Luo, Birong
AU - Shivayogimath, Abhay
AU - Smitshuysen, Anne Lyck
AU - Thomsen, Joachim Dahl
AU - Booth, Tim
AU - Gammelgaard, Lene
AU - Zultak, Johanna
AU - Jessen, Bjarke Sørensen
AU - Bøggild, Peter
AU - Petersen, Dirch Hjorth
PY - 2017
Y1 - 2017
N2 - With the increasing availability of large-area graphene, the ability to rapidly and accurately assess the quality of the electrical properties has become critically important. For practical applications, spatial variability in carrier density and carrier mobility must be controlled and minimized. We present a simple framework for assessing the quality and homogeneity of large-area graphene devices. The field effect in both exfoliated graphene devices encapsulated in hexagonal boron nitride and chemical vapor-deposited (CVD) devices was measured in dual current–voltage configurations and used to derive a single, gate-dependent effective shape factor, ß, for each device. ß is a sensitive indicator of spatial homogeneity that can be obtained from samples of arbitrary shape. All 50 devices investigated in this study show a variation (up to tenfold) in ß as a function of the gate bias. Finite element simulations suggest that spatial doping inhomogeneity, rather than mobility inhomogeneity, is the primary cause of the gate dependence of ß, and that measurable variations of ß can be caused by doping variations as small as 1010 cm−2. Our results suggest that local variations in the position of the Dirac point alter the current flow and thus the effective sample shape as a function of the gate bias. We also found that such variations lead to systematic errors in carrier mobility calculations, which can be revealed by inspecting the corresponding ß factor.
AB - With the increasing availability of large-area graphene, the ability to rapidly and accurately assess the quality of the electrical properties has become critically important. For practical applications, spatial variability in carrier density and carrier mobility must be controlled and minimized. We present a simple framework for assessing the quality and homogeneity of large-area graphene devices. The field effect in both exfoliated graphene devices encapsulated in hexagonal boron nitride and chemical vapor-deposited (CVD) devices was measured in dual current–voltage configurations and used to derive a single, gate-dependent effective shape factor, ß, for each device. ß is a sensitive indicator of spatial homogeneity that can be obtained from samples of arbitrary shape. All 50 devices investigated in this study show a variation (up to tenfold) in ß as a function of the gate bias. Finite element simulations suggest that spatial doping inhomogeneity, rather than mobility inhomogeneity, is the primary cause of the gate dependence of ß, and that measurable variations of ß can be caused by doping variations as small as 1010 cm−2. Our results suggest that local variations in the position of the Dirac point alter the current flow and thus the effective sample shape as a function of the gate bias. We also found that such variations lead to systematic errors in carrier mobility calculations, which can be revealed by inspecting the corresponding ß factor.
KW - CVD graphene
KW - Doping inhomogeneity
KW - Electrical measurements
KW - van der Pauw
KW - hBN-encapsulated graphene
KW - Finite element simulations
KW - Raman mapping
U2 - 10.1007/s12274-017-1570-y
DO - 10.1007/s12274-017-1570-y
M3 - Journal article
VL - 10
SP - 3596
EP - 3605
JO - Nano Research
JF - Nano Research
SN - 1998-0124
IS - 10
ER -