Qualitative analysis of scanning gate microscopy on epitaxial graphene

David M. A. Mackenzie*, Vishal Panchal, Hector Corte-Leon, Dirch H. Petersen, Olga Kazakova

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

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Abstract

We present scanning gate microscopy (SGM) studies of graphene Hall-cross devices where bi-layer graphene (2LG) regions show unexpected signal inversion relative to single-layer graphene (1LG), an observation reproduced via finite element modelling of the current densities. This is attributed to gate-induced charge carrier redistribution between the two layers in 2LG. Hall cross devices were fabricated from epitaxial graphene 6H-SiC(0001) and were covered by 1LG/2LG with the area ratio of 85: 15%, respectively. Local electric-field sensitivity maps of the devices were obtained in two different measurement geometries using electrical SGM with a conductive tip, where it was observed that the voltage of 2LG islands was inverted relative to anticipated reference maps. Finite element modelling of the current densities and voltage response showed good qualitative agreement with the SGM maps when the effect of the gate was reversed for 2LG. The behaviour is attributed to gate-induced charge carrier redistribution between the two layers in 2LG. The model can be used generally as a tool to predict mixed 1LG/2LG response to electric field. Moreover, regions near the corners of the device show the highest sensitivity when the local electric field was applied to the scanning probe microscopy tip. These regions are capable of detecting highly local electric fields down to 110 kV cm-1.

Original languageEnglish
Article number025023
Journal2D materials
Volume6
Issue number2
Number of pages10
ISSN2053-1583
DOIs
Publication statusPublished - 2019

Keywords

  • Scanning gate microscopy
  • Epitaxial graphene
  • Finite element simulations
  • KPFM
  • Electric field effect
  • eElectrical sensitivity

Cite this

Mackenzie, D. M. A., Panchal, V., Corte-Leon, H., Petersen, D. H., & Kazakova, O. (2019). Qualitative analysis of scanning gate microscopy on epitaxial graphene. 2D materials, 6(2), [025023]. https://doi.org/10.1088/2053-1583/ab0572
Mackenzie, David M. A. ; Panchal, Vishal ; Corte-Leon, Hector ; Petersen, Dirch H. ; Kazakova, Olga. / Qualitative analysis of scanning gate microscopy on epitaxial graphene. In: 2D materials. 2019 ; Vol. 6, No. 2.
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abstract = "We present scanning gate microscopy (SGM) studies of graphene Hall-cross devices where bi-layer graphene (2LG) regions show unexpected signal inversion relative to single-layer graphene (1LG), an observation reproduced via finite element modelling of the current densities. This is attributed to gate-induced charge carrier redistribution between the two layers in 2LG. Hall cross devices were fabricated from epitaxial graphene 6H-SiC(0001) and were covered by 1LG/2LG with the area ratio of 85: 15{\%}, respectively. Local electric-field sensitivity maps of the devices were obtained in two different measurement geometries using electrical SGM with a conductive tip, where it was observed that the voltage of 2LG islands was inverted relative to anticipated reference maps. Finite element modelling of the current densities and voltage response showed good qualitative agreement with the SGM maps when the effect of the gate was reversed for 2LG. The behaviour is attributed to gate-induced charge carrier redistribution between the two layers in 2LG. The model can be used generally as a tool to predict mixed 1LG/2LG response to electric field. Moreover, regions near the corners of the device show the highest sensitivity when the local electric field was applied to the scanning probe microscopy tip. These regions are capable of detecting highly local electric fields down to 110 kV cm-1.",
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Mackenzie, DMA, Panchal, V, Corte-Leon, H, Petersen, DH & Kazakova, O 2019, 'Qualitative analysis of scanning gate microscopy on epitaxial graphene', 2D materials, vol. 6, no. 2, 025023. https://doi.org/10.1088/2053-1583/ab0572

Qualitative analysis of scanning gate microscopy on epitaxial graphene. / Mackenzie, David M. A.; Panchal, Vishal; Corte-Leon, Hector; Petersen, Dirch H.; Kazakova, Olga.

In: 2D materials, Vol. 6, No. 2, 025023, 2019.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Qualitative analysis of scanning gate microscopy on epitaxial graphene

AU - Mackenzie, David M. A.

AU - Panchal, Vishal

AU - Corte-Leon, Hector

AU - Petersen, Dirch H.

AU - Kazakova, Olga

PY - 2019

Y1 - 2019

N2 - We present scanning gate microscopy (SGM) studies of graphene Hall-cross devices where bi-layer graphene (2LG) regions show unexpected signal inversion relative to single-layer graphene (1LG), an observation reproduced via finite element modelling of the current densities. This is attributed to gate-induced charge carrier redistribution between the two layers in 2LG. Hall cross devices were fabricated from epitaxial graphene 6H-SiC(0001) and were covered by 1LG/2LG with the area ratio of 85: 15%, respectively. Local electric-field sensitivity maps of the devices were obtained in two different measurement geometries using electrical SGM with a conductive tip, where it was observed that the voltage of 2LG islands was inverted relative to anticipated reference maps. Finite element modelling of the current densities and voltage response showed good qualitative agreement with the SGM maps when the effect of the gate was reversed for 2LG. The behaviour is attributed to gate-induced charge carrier redistribution between the two layers in 2LG. The model can be used generally as a tool to predict mixed 1LG/2LG response to electric field. Moreover, regions near the corners of the device show the highest sensitivity when the local electric field was applied to the scanning probe microscopy tip. These regions are capable of detecting highly local electric fields down to 110 kV cm-1.

AB - We present scanning gate microscopy (SGM) studies of graphene Hall-cross devices where bi-layer graphene (2LG) regions show unexpected signal inversion relative to single-layer graphene (1LG), an observation reproduced via finite element modelling of the current densities. This is attributed to gate-induced charge carrier redistribution between the two layers in 2LG. Hall cross devices were fabricated from epitaxial graphene 6H-SiC(0001) and were covered by 1LG/2LG with the area ratio of 85: 15%, respectively. Local electric-field sensitivity maps of the devices were obtained in two different measurement geometries using electrical SGM with a conductive tip, where it was observed that the voltage of 2LG islands was inverted relative to anticipated reference maps. Finite element modelling of the current densities and voltage response showed good qualitative agreement with the SGM maps when the effect of the gate was reversed for 2LG. The behaviour is attributed to gate-induced charge carrier redistribution between the two layers in 2LG. The model can be used generally as a tool to predict mixed 1LG/2LG response to electric field. Moreover, regions near the corners of the device show the highest sensitivity when the local electric field was applied to the scanning probe microscopy tip. These regions are capable of detecting highly local electric fields down to 110 kV cm-1.

KW - Scanning gate microscopy

KW - Epitaxial graphene

KW - Finite element simulations

KW - KPFM

KW - Electric field effect

KW - eElectrical sensitivity

U2 - 10.1088/2053-1583/ab0572

DO - 10.1088/2053-1583/ab0572

M3 - Journal article

VL - 6

JO - 2D materials

JF - 2D materials

SN - 2053-1583

IS - 2

M1 - 025023

ER -