Doping of graphene exfoliated on SrTiO<sub>3</sub>

Bußmann, Benedict Kleine; Ochedowski, Oliver; Schleberger, Marika

doi:10.1088/0957-4484/22/26/265703

Cited by 34 publications

(27 citation statements)

References 33 publications

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“…This defines work functions of Φ 1LG ~ 4.55 ± 0.02 eV and Φ 2LG ~ 4.44 ± 0.02 eV. These work function values are within the range of previously reported results of 4.41–4.57 eV for 1LG measured with FM-KPFM621. It should be noted that the work function of graphene depends on the carrier density and is, therefore exceptionally sensitive to substrate and environmental gating due to its two-dimensional nature.…”

Section: Resultssupporting

confidence: 87%

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Standardization of surface potential measurements of graphene domains

Panchal

Pearce

Yakimova

et al. 2013

Sci Rep

213

198

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We compare the three most commonly used scanning probe techniques to obtain a reliable value of the work function in graphene domains of different thickness. The surface potential (SP) of graphene is directly measured in Hall bar geometry via a combination of electrical functional microscopy and spectroscopy techniques, which enables calibrated work function measurements of graphene domains in ambient conditions with values Φ1LG ~4.55 ± 0.02 eV and Φ2LG ~ 4.44 ± 0.02 eV for single- and bi-layer, respectively. We demonstrate that frequency-modulated Kelvin probe force microscopy (FM-KPFM) provides more accurate measurement of the SP than amplitude-modulated (AM)-KPFM. The discrepancy between experimental results obtained by different techniques is discussed. In addition, we use FM-KPFM for contactless measurements of the specific components of the device resistance. We show a strong non-Ohmic behavior of the electrode-graphene contact resistance and extract the graphene channel resistivity.

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Section: Resultssupporting

confidence: 87%

“…For example, the published values were reported to change with varying lab ambient, i.e. the change of work function and SP due to adsorbates being <50 meV6 and ~130 mV21, respectively.…”

Section: Resultsmentioning

confidence: 99%

Standardization of surface potential measurements of graphene domains

Panchal

Pearce

Yakimova

et al. 2013

Sci Rep

213

198

View full text Add to dashboard Cite

show abstract

“…The work function value of graphite can be assigned to few layer graphene areas where the surface potential depends on the layer number29. This procedure yields Φ FLG = Φ Graphite = 4.65 eV for few layer graphene (FLG).…”

Section: Resultsmentioning

confidence: 99%

Graphene on Mica - Intercalated Water Trapped for Life

Ochedowski

Bußmann

Schleberger

2014

Sci Rep

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In this work we study the effect of thermal processing of exfoliated graphene on mica with respect to changes in graphene morphology and surface potential. Mild annealing to temperatures of about 200°C leads to the removal of small amounts of intercalated water at graphene edges. By heating to 600°C the areas without intercalated water are substantially increased enabling a quantification of the charge transfer properties of the water layer by locally resolved Kelvin probe force microscopy data. A complete removal on a global scale cannot be achieved because mica begins to decompose at temperatures above 600°C. By correlating Kelvin probe force microscopy and Raman spectroscopy maps we find a transition from p-type to n-type doping of graphene during thermal processing which is driven by the dehydration of the mica substrate and an accumulation of defects in the graphene sheet.

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“…Note that the EFM image was taken with V probe = +2V, where the contrast of the individual domains is opposite to surface potential (see Figure 2); (b) Band structure of n-doped 1 LG and 2 LG that are in electrical contact with each other. (2) FM-KPFM [108] Note:…”

Section: Calibrated Work Functions Of Single-and Double-layer Graphenementioning

confidence: 99%

Epitaxial Graphene and Graphene–Based Devices Studied by Electrical Scanning Probe Microscopy

2013

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Abstract:We present local electrical characterization of epitaxial graphene grown on both Si-and C-faces of 4H-SiC using Electrostatic Force Microscopy and Kelvin Probe Force Microscopy in ambient conditions and at elevated temperatures. These techniques provide a straightforward identification of graphene domains with various thicknesses on the substrate where topographical determination is hindered by adsorbates and SiC terraces. We also use Electrostatic Force Spectroscopy which allows quantitative surface potential measurements with high spatial resolution. Using these techniques, we study evolution of a layer of atmospheric water as a function of temperature, which is accompanied by a significant change of the absolute surface potential difference. We show that the nanoscale wettability of the material is strongly dependent on the number of graphene layers, where hydrophobicity increases with graphene thickness. We also use micron-sized graphene Hall bars with gold electrodes to calibrate work function of the electrically conductive probe and precisely and quantitatively define the work functions for single-and double-layer graphene.

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Doping of graphene exfoliated on SrTiO₃

Cited by 34 publications

References 33 publications

Standardization of surface potential measurements of graphene domains

Standardization of surface potential measurements of graphene domains

Graphene on Mica - Intercalated Water Trapped for Life

Epitaxial Graphene and Graphene–Based Devices Studied by Electrical Scanning Probe Microscopy

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Doping of graphene exfoliated on SrTiO3

Cited by 34 publications

References 33 publications

Standardization of surface potential measurements of graphene domains

Standardization of surface potential measurements of graphene domains

Graphene on Mica - Intercalated Water Trapped for Life

Epitaxial Graphene and Graphene–Based Devices Studied by Electrical Scanning Probe Microscopy

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Product

Resources

About

Doping of graphene exfoliated on SrTiO₃