http://www.cnr.it/ontology/cnr/individuo/prodotto/ID202603

Mapping the Density of Scattering Centers Limiting the Electron Mean Free Path in Graphene (Articolo in rivista)

Type

Articolo in rivista (Classe)
Prodotto della ricerca (Classe)

Label

Mapping the Density of Scattering Centers Limiting the Electron Mean Free Path in Graphene (Articolo in rivista) (literal)

Anno

2011-01-01T00:00:00+01:00 (literal)

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#doi

10.1021/nl2020922 (literal)

Alternative label

F. Giannazzo (1); S. Sonde (1,2); R. Lo Nigro (1); E. Rimini (1); V. Raineri (1) (2011)
Mapping the Density of Scattering Centers Limiting the Electron Mean Free Path in Graphene
in Nano letters (Print); ACS, American chemical society, Washington, DC (Stati Uniti d'America)
(literal)

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#autori

F. Giannazzo (1); S. Sonde (1,2); R. Lo Nigro (1); E. Rimini (1); V. Raineri (1) (literal)

Pagina inizio

4612 (literal)

Pagina fine

4618 (literal)

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#numeroVolume

11 (literal)

Rivista

Nano letters (Rivista)

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#pagineTotali

6 (literal)

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#numeroFascicolo

11 (literal)

Note

ISI Web of Science (WOS) (literal)

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#affiliazioni

(1) CNR IMM, I-95121 Catania, Italy (2) Scuola Super Catania, I-95123 Catania, Italy (literal)

Titolo

Mapping the Density of Scattering Centers Limiting the Electron Mean Free Path in Graphene (literal)

Abstract

Recently, giant carrier mobility mu (>10(5) cm(2) V-1 s(-1)) and micrometer electron mean free path (1) have been measured in suspended gaphene or in graphene encapsulated between inert and ultraflat BN layers. Much lower mu values (10000-20000 cm(2) V-1 s(-1)) are typically reported in graphene on common substrates (SiO2, SiC) used for device fabricaticn. The debate on the factors limiting graphene electron mean free path is still open with charged impurities (CI) and resonant scatterers (RS) indicated as the most probable candidates. As a matter of fact, the inhomogeneous distribution of such scattering sources in graphene is responsible of nanoscale lateral inhomogeneities in the electronic properties, which could affect the behavior of graphene nanodevices. Hence, high resolution two-dimensional (2D) mapping of their density is very important. Here, we used scanning capacitance microscopy/spectroscopy to obtain 2D maps of l in graphene on substrates with different dielectric permittivities, that is, SiO2 (kappa(SiO2) = 3.9), 4H-SiC (0001) (kappa(SiC) = 9.7) and the very-high-kappa perovskite strontium titanate, SrTiO3 (001), briefly STO (kappa(STO) = 330). After measuring l versus the gate bias V-g on an array of points on graphene, maps of the CI density (N-CI) have been determined by the neutrality point shift from V-g = 0 V in each curve, whereas maps of the RS density (N-RS) have been extracted by fitting the dependence of l on the carrier density (n). Laterally inhomogeneous densities of CI and RS have been found. The RS distribution exhibits an average value similar to 3 x 10(10) cm(-2) independently on the substrate. For the first time, a clear correlation between the minima in the l map and the maxima in the N-CI map is obtained for graphene on SiO2 and 4H-SiC, indicating that CI are the main source of the lateral inhomogeneity of l. On the contrary, the l and N-CI maps are uncorrelated in graphene on STO, while a clear correlation is found between l and N-RS maps. This demonstrates a very efficient dielectric screening of CI in gaphene on STO and the role of RS as limiting factor for electron mean free path. (literal)

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