Limits...
Multidimensional characterization, Landau levels and Density of States in epitaxial graphene grown on SiC substrates.

Camara N, Jouault B, Jabakhanji B, Caboni A, Tiberj A, Consejo C, Godignon P, Camassel J - Nanoscale Res Lett (2011)

Bottom Line: Raman spectroscopy shows evidence of the almost free-standing character of these monolayer graphene sheets, which was confirmed by magneto-transport measurements.On the best samples, we find a moderate p-type doping, a high-carrier mobility and resolve the half-integer quantum Hall effect typical of high-quality graphene samples.A rough estimation of the density of states is given from temperature measurements.

View Article: PubMed Central - HTML - PubMed

Affiliation: Laboratoire Charles Coulomb, UMR 5221 CNRS-UM2, Place Eugène Bataillon, 34095 Montpellier Cedex 5, France. jouault@ges.univ-montp2.fr.

ABSTRACT
Using high-temperature annealing conditions with a graphite cap covering the C-face of, both, on axis and 8° off-axis 4H-SiC samples, large and homogeneous single epitaxial graphene layers have been grown. Raman spectroscopy shows evidence of the almost free-standing character of these monolayer graphene sheets, which was confirmed by magneto-transport measurements. On the best samples, we find a moderate p-type doping, a high-carrier mobility and resolve the half-integer quantum Hall effect typical of high-quality graphene samples. A rough estimation of the density of states is given from temperature measurements.

No MeSH data available.


Related in: MedlinePlus

AFM images of continuous and almost free standing monolayer graphene islands grown on the C-face of an 8° off-axis 4H-SiC substrate. (a) at a large scale, the zoom in (b) showing the wrinkle and the step bunched character of the SiC surface below and (c) a layer scratched by an AFM tip.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3211189&req=5

Figure 2: AFM images of continuous and almost free standing monolayer graphene islands grown on the C-face of an 8° off-axis 4H-SiC substrate. (a) at a large scale, the zoom in (b) showing the wrinkle and the step bunched character of the SiC surface below and (c) a layer scratched by an AFM tip.

Mentions: In Figure 2a we show a typical AFM image of such a SLEG islands. When zooming, wrinkles become clearly visible in Figure 2 and show evidence of the continuity and strain-free character of the monolayers. Below the graphene islands, the step-bunched areas of the SiC surface are also clearly visible in both SEM and AFM pictures. The corresponding terraces are typically 100 nm wide and less than 2 nm high. A last evidence of the fact that the first layer of graphene is not coupled with the substrate and continuous despite the step-bunched surface is the facility with which we can remove the SLEG layer with an AFM tip. The result presented with the AFM picture of Figure 2c demonstrates the almost free-standing and continuous character of the grown SLEG.


Multidimensional characterization, Landau levels and Density of States in epitaxial graphene grown on SiC substrates.

Camara N, Jouault B, Jabakhanji B, Caboni A, Tiberj A, Consejo C, Godignon P, Camassel J - Nanoscale Res Lett (2011)

AFM images of continuous and almost free standing monolayer graphene islands grown on the C-face of an 8° off-axis 4H-SiC substrate. (a) at a large scale, the zoom in (b) showing the wrinkle and the step bunched character of the SiC surface below and (c) a layer scratched by an AFM tip.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211189&req=5

Figure 2: AFM images of continuous and almost free standing monolayer graphene islands grown on the C-face of an 8° off-axis 4H-SiC substrate. (a) at a large scale, the zoom in (b) showing the wrinkle and the step bunched character of the SiC surface below and (c) a layer scratched by an AFM tip.
Mentions: In Figure 2a we show a typical AFM image of such a SLEG islands. When zooming, wrinkles become clearly visible in Figure 2 and show evidence of the continuity and strain-free character of the monolayers. Below the graphene islands, the step-bunched areas of the SiC surface are also clearly visible in both SEM and AFM pictures. The corresponding terraces are typically 100 nm wide and less than 2 nm high. A last evidence of the fact that the first layer of graphene is not coupled with the substrate and continuous despite the step-bunched surface is the facility with which we can remove the SLEG layer with an AFM tip. The result presented with the AFM picture of Figure 2c demonstrates the almost free-standing and continuous character of the grown SLEG.

Bottom Line: Raman spectroscopy shows evidence of the almost free-standing character of these monolayer graphene sheets, which was confirmed by magneto-transport measurements.On the best samples, we find a moderate p-type doping, a high-carrier mobility and resolve the half-integer quantum Hall effect typical of high-quality graphene samples.A rough estimation of the density of states is given from temperature measurements.

View Article: PubMed Central - HTML - PubMed

Affiliation: Laboratoire Charles Coulomb, UMR 5221 CNRS-UM2, Place Eugène Bataillon, 34095 Montpellier Cedex 5, France. jouault@ges.univ-montp2.fr.

ABSTRACT
Using high-temperature annealing conditions with a graphite cap covering the C-face of, both, on axis and 8° off-axis 4H-SiC samples, large and homogeneous single epitaxial graphene layers have been grown. Raman spectroscopy shows evidence of the almost free-standing character of these monolayer graphene sheets, which was confirmed by magneto-transport measurements. On the best samples, we find a moderate p-type doping, a high-carrier mobility and resolve the half-integer quantum Hall effect typical of high-quality graphene samples. A rough estimation of the density of states is given from temperature measurements.

No MeSH data available.


Related in: MedlinePlus