Electron scattering on microscopic corrugations in graphene

Katsnelson, M. I.; Geǐm, A. K.

doi:10.1098/rsta.2007.2157

Cited by 528 publications

(531 citation statements)

References 49 publications

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“…More specifically, intrinsic ripples are expected to influence the electrical properties of graphene by changing band gap [239], creating polarized carrier puddles [240] and inducing pseudo-magnetic fields [241]. Whereas wrinkles and crumples result in several electronic phenomena, such as electron-hole puddles [189,242], carrier scattering [195,243], band gap opening [244], suppression of weak localization [245] and quantum corrections [246]. …”

Section: Disorders In Graphene Structurementioning

confidence: 99%

Structure of graphene and its disorders: a review

Gao

Lee

et al. 2018

Science and Technology of Advanced Materials

487

187

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Monolayer graphene exhibits extraordinary properties owing to the unique, regular arrangement of atoms in it. However, graphene is usually modified for specific applications, which introduces disorder. This article presents details of graphene structure, including sp2 hybridization, critical parameters of the unit cell, formation of σ and π bonds, electronic band structure, edge orientations, and the number and stacking order of graphene layers. We also discuss topics related to the creation and configuration of disorders in graphene, such as corrugations, topological defects, vacancies, adatoms and sp3-defects. The effects of these disorders on the electrical, thermal, chemical and mechanical properties of graphene are analyzed subsequently. Finally, we review previous work on the modulation of structural defects in graphene for specific applications.

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Section: Disorders In Graphene Structurementioning

confidence: 99%

Structure of graphene and its disorders: a review

Gao

Lee

et al. 2018

Science and Technology of Advanced Materials

487

187

View full text Add to dashboard Cite

show abstract

“…In the NSG sample the mfp increases with carrier density for n sat <n <4 x 10 11 cm -2 reflecting dominant Coulomb scattering 16 there. This trend which is not seen in SG samples, again suggests almost complete absence of Coulomb scattering 16,24 .…”

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confidence: 94%

“…The substrate-induced charge inhomogeneity is particularly deleterious near the DP where screening is weak, 14,15 leading to reduced carrier mobility there. In addition, the atomic roughness of the substrate introduces short range scattering centers and may contribute to quench-condensation of ripples within the graphene layer 16 .In order to eliminate substrate induced perturbations, graphene films were suspended from Au/Ti contacts to bridge over a trench in a SiO 2 substrate. In contrast to prior realizations of suspended graphene 17,18 which did not provide electrical contacts for transport measurements, the SG devices described here incorporate multiple electrodes that allow 4-lead transport measurements.…”

mentioning

confidence: 99%

mentioning

confidence: 99%

“…compared to ~ 2,000-20,000 cm 2 /Vs in the best NSG samples. Since at low densities the mobility is mostly determined by long range Coulomb scattering 16 (short range scattering is very weak near the DP due to the small density of states 24 ), the difference in mobility between the SG and NSG samples is naturally attributed to substrate-induced charge inhomogeneity. In this picture the removal of the substrate in the SG samples eliminates the primary source of Coulomb scattering, the trapped charges.…”

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confidence: 99%

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Approaching ballistic transport in suspended graphene

et al. 2008

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The recent discovery of methods to isolate graphene 1-3 , a one-atom-thick layer of crystalline carbon, has raised the possibility of a new class of nano-electronics devices based on the extraordinary electrical transport and unusual physical properties 4,5 of this material. However, the experimental realization of devices displaying these properties was, until now, hampered by the influence of the ambient environment, primarily the substrate. Here we report on the fabrication of Suspended Graphene (SG) devices and on studies of their electrical transport properties. In these devices, environmental disturbances were minimized allowing unprecedented access to the intrinsic properties of graphene close to the Dirac Point (DP) where the energy dispersion of the carriers and their density-of-states vanish linearly giving rise to a range of exotic physical properties. We show that charge inhomogeneity is reduced by almost one order of magnitude compared to that in Non-Suspended Graphene (NSG) devices. Moreover, near the DP, the mobility exceeds 100,000 cm 2 /Vs, approaching theoretical predictions for evanescent transport in the ballistic model. The low energy excitation spectrum of graphene mimics relativistic particles -massless Dirac fermions (DF) -with an electron-hole symmetric conical energy dispersion and .vanishing density of states at the DP. Such unusual spectrum is expected to produce 1 novel electronic properties such as negative index of refraction 6 , specular Andreev reflections at graphene-superconductor junctions 7,8 , evanescent transport 9 , anomalous phonon softening 10 , etc. A basic assumption behind these intriguing predictions is that the graphene layer is minimally affected by interactions with the environment. However in reality the environment 11,12 and in particular the substrate 13 , can be quite invasive for such ultra-thin films. For example, the carrier mobility in graphene deposited on a substrate such as Si/SiO 2 deteriorates due to trapped charges in the oxide or to contaminants that get trapped at the graphene-substrate interface during fabrication. The substrate-induced charge inhomogeneity is particularly deleterious near the DP where screening is weak, 14,15 leading to reduced carrier mobility there. In addition, the atomic roughness of the substrate introduces short range scattering centers and may contribute to quench-condensation of ripples within the graphene layer 16 .In order to eliminate substrate induced perturbations, graphene films were suspended from Au/Ti contacts to bridge over a trench in a SiO 2 substrate. In contrast to prior realizations of suspended graphene 17,18 which did not provide electrical contacts for transport measurements, the SG devices described here incorporate multiple electrodes that allow 4-lead transport measurements. The SG devices employed here were fabricated from conventional NSG devices using wet chemical etching (see supporting online material). In a typical SG device, shown in Figure 1b, the graphene layer is suspended from the voltage l...

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