Limits...
Lateral homogeneity of the electronic properties in pristine and ion-irradiated graphene probed by scanning capacitance spectroscopy.

Giannazzo F, Sonde S, Rimini E, Raineri V - Nanoscale Res Lett (2011)

Bottom Line: In this article, a scanning probe method based on nanoscale capacitance measurements was used to investigate the lateral homogeneity of the electron mean free path both in pristine and ion-irradiated graphene.The local variations in the electronic transport properties were explained taking into account the scattering of electrons by charged impurities and point defects (vacancies).The local density of the charged impurities and vacancies were determined for different irradiated ion fluences.

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Affiliation: CNR-IMM, Strada VIII, 5, Zona Industriale, 95121, Catania, Italy. filippo.giannazzo@imm.cnr.it.

ABSTRACT
In this article, a scanning probe method based on nanoscale capacitance measurements was used to investigate the lateral homogeneity of the electron mean free path both in pristine and ion-irradiated graphene. The local variations in the electronic transport properties were explained taking into account the scattering of electrons by charged impurities and point defects (vacancies). Electron mean free path is mainly limited by charged impurities in unirradiated graphene, whereas an important role is played by lattice vacancies after irradiation. The local density of the charged impurities and vacancies were determined for different irradiated ion fluences.

No MeSH data available.


Local electron mean free path versus the Fermi energy in a selected position on pristine graphene.
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Figure 3: Local electron mean free path versus the Fermi energy in a selected position on pristine graphene.

Mentions: It has been recently demonstrated that the effective area Aeff obtained by local capacitance measurements is related to the local electron mean free path l in graphene by Aeff = πl2 [20]. In Figure 3, l is reported versus the evaluated Fermi energy. It can be noted that l is almost independent of EF close to the Dirac point. The behavior close to the Dirac point is consistent with the common adopted picture of the 2DEG split in a landscape of adjacent "electron-hole puddles" [21]. Close to the Dirac point, the effect of a gate bias is limited to a redistribution of carriers between the electrons and holes puddles without significantly changing the total carrier density. Figure 3 shows also that, for /EF/ > 25 meV, l increases linearly with EF both in the hole and electron branches. This linear dependence gives indication on the main scattering mechanisms limiting l in our graphene samples.


Lateral homogeneity of the electronic properties in pristine and ion-irradiated graphene probed by scanning capacitance spectroscopy.

Giannazzo F, Sonde S, Rimini E, Raineri V - Nanoscale Res Lett (2011)

Local electron mean free path versus the Fermi energy in a selected position on pristine graphene.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211153&req=5

Figure 3: Local electron mean free path versus the Fermi energy in a selected position on pristine graphene.
Mentions: It has been recently demonstrated that the effective area Aeff obtained by local capacitance measurements is related to the local electron mean free path l in graphene by Aeff = πl2 [20]. In Figure 3, l is reported versus the evaluated Fermi energy. It can be noted that l is almost independent of EF close to the Dirac point. The behavior close to the Dirac point is consistent with the common adopted picture of the 2DEG split in a landscape of adjacent "electron-hole puddles" [21]. Close to the Dirac point, the effect of a gate bias is limited to a redistribution of carriers between the electrons and holes puddles without significantly changing the total carrier density. Figure 3 shows also that, for /EF/ > 25 meV, l increases linearly with EF both in the hole and electron branches. This linear dependence gives indication on the main scattering mechanisms limiting l in our graphene samples.

Bottom Line: In this article, a scanning probe method based on nanoscale capacitance measurements was used to investigate the lateral homogeneity of the electron mean free path both in pristine and ion-irradiated graphene.The local variations in the electronic transport properties were explained taking into account the scattering of electrons by charged impurities and point defects (vacancies).The local density of the charged impurities and vacancies were determined for different irradiated ion fluences.

View Article: PubMed Central - HTML - PubMed

Affiliation: CNR-IMM, Strada VIII, 5, Zona Industriale, 95121, Catania, Italy. filippo.giannazzo@imm.cnr.it.

ABSTRACT
In this article, a scanning probe method based on nanoscale capacitance measurements was used to investigate the lateral homogeneity of the electron mean free path both in pristine and ion-irradiated graphene. The local variations in the electronic transport properties were explained taking into account the scattering of electrons by charged impurities and point defects (vacancies). Electron mean free path is mainly limited by charged impurities in unirradiated graphene, whereas an important role is played by lattice vacancies after irradiation. The local density of the charged impurities and vacancies were determined for different irradiated ion fluences.

No MeSH data available.