Room temperature velocity saturation in intrinsic graphene

Shishir, Razib; Ferry, D. K.; Goodnick, Stephen M.

doi:10.1088/1742-6596/193/1/012118

Cited by 26 publications

(22 citation statements)

References 17 publications

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“…Recently, the phenomena of current saturation have attracted intense interest. 7,8,10,11,36 It is found that the current saturation in graphene at high electric field depends on the optical phonon frequency ω ph and equilibrium current carrier density n eq . The former is a parameter independent of electric control, and the latter is controlled through the chemical potential µ.…”

Section: B Steady-state Current At Large Fieldsmentioning

confidence: 99%

Nonequilibrium excitations and transport of Dirac electrons in electric-field-driven graphene

Han

2018

Phys. Rev. B

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We investigate nonequilibrium excitations and charge transport in charge-neutral graphene driven with dc electric field by using the nonequilibrium Green's function technique. Due to the vanishing Fermi surface, electrons are subject to non-trivial nonequilibrium excitations such as highly anisotropic momentum distribution of electron-hole pairs, an analog of the Schwinger effect. We show that the electron-hole excitations, initiated by the Landau-Zener tunneling with a superlinear IV relation I ∝ E 3/2 , reaches a steady state dominated by the dissipation due to optical phonons, resulting in a marginally sublinear IV with I ∝ E, in agreement with recent experiments. The linear IV starts to show the sign of current saturation as the graphene is doped away from the Dirac point, and recovers the semi-classical relation for the saturated velocity. We give a detailed discussion on the nonequilibrium charge creation and the relation between the electron-phonon scattering rate and the electric field in the steady-state limit. We explain how the apparent Ohmic IV is recovered near the Dirac point. We propose a mechanism where the peculiar nonequilibrium electron-hole creation can be utilized in an infra-red device.

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Section: B Steady-state Current At Large Fieldsmentioning

confidence: 99%

Nonequilibrium excitations and transport of Dirac electrons in electric-field-driven graphene

Han

2018

Phys. Rev. B

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“…Recent theoretical work on the high-field response of graphene indicates that the unique electronic properties of graphene lead to remarkably strong optical nonlinearities in the THz and IR regime [17][18][19][20][21][22][23][24]. The predicted strong nonlinear responses of graphene make it an attractive material for active photonic devices.…”

Section: Introductionmentioning

confidence: 99%

“…Furthermore, as the internal electric field inside electronic devices could possibly reach 100 kV cm −1 , it is desirable to determine the maximum field at which graphene still behaves linearly. Transport in a strong field has also been studied theoretically, and nonlinear relationships between current and electric field are predicted [17][18][19][20]. Harmonic generation in graphene under a strong THz field has been predicted by several groups using different theoretical approaches [21][22][23][24].…”

Section: Introductionmentioning

confidence: 99%

High-field terahertz response of graphene

Paul

Chang²,

Thompson

et al. 2013

New J. Phys.

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“…At elevated (room) temperatures, in contrast to the low temperature situation [13], the interband transitions associated with optical phonons can be the dominant mechanism of the recombination [16]. The energy relaxation of electrons and holes in GLs can also be mainly due to interaction with optical phonons [17]. In such a case, the optical photons emitted by the photogenerated electrons and holes can accumulate in GL, so that the optical phonon system is heated as well.…”

Section: Introductionmentioning

confidence: 99%

Effect of Heating and Cooling of Photogenerated Electron–Hole Plasma in Optically Pumped Graphene on Population Inversion

Ryzhii

Mitin

et al. 2011

Jpn. J. Appl. Phys.

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We study the characteristics of photogenerated electron-hole plasma in optically pumped graphene layers at elevated (room) temperatures when the interband and intraband processes of emission and absorption of optical phonons play a crucial role. The electron-hole plasma heating and cooling as well as the effect of nonequilibrium optical phonons are taken into account. The dependences of the quasi-Fermi energy and effective temperature of optically pumped graphene layers on the intensity of pumping radiation are calculated. The variation of the frequency dependences dynamic conductivity with increasing pumping intensity as well as the conditions when this conductivity becomes negative in a certain range of frequencies are considered. The effects under consideration can markedly influence the achievement of the negative dynamic conductivity in optically pumped graphene layers associated with the population inversion and, hence, the realization graphene-based terahertz and infrared lasers operating at room temperatures.

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Room temperature velocity saturation in intrinsic graphene

Cited by 26 publications

References 17 publications

Nonequilibrium excitations and transport of Dirac electrons in electric-field-driven graphene

Nonequilibrium excitations and transport of Dirac electrons in electric-field-driven graphene

High-field terahertz response of graphene

Effect of Heating and Cooling of Photogenerated Electron–Hole Plasma in Optically Pumped Graphene on Population Inversion

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