Temperature-Dependent Transport in Suspended Graphene

Abstract

The resistivity of ultra-clean suspended graphene is strongly temperature (T ) dependent for 5 K< T < 240 K. At T ∼ 5 K transport is near-ballistic in a device of ∼ 2 µm dimension and a mobility ∼ 170, 000 cm 2 /Vs. At large carrier density, n > 0.5×10 11 cm −2 , the resistivity increases with increasing T and is linear above 50 K, suggesting carrier scattering from acoustic phonons. At T = 240 K the mobility is ∼ 120, 000 cm 2 /Vs, higher than in any known semiconductor. At the charge neutral point we observe a non-universal conductivity that decreases with decreasing T , consistent with a density inhomogeneity <10 8 cm −2 .

Unraveling the acoustic electron-phonon interaction in graphene

“…It is seen to reproduce the relaxation time based on the full matrix elements very well for the energy range shown. While the extracted value for the acoustic deformation potential is much smaller than experimental values, 5,[7][8][9]11 it is in better agreement with other ab initio results yielding 4.5 eV. 31 We also note that our findings for the value of the effective deformation potential are in stark contrast to those of Ref.…”

“…The linear temperature dependence characteristic for acoustic phonon scattering has so far been observed in both supported 5,[7][8][9][10] and suspended 11 graphene samples. With the recent improvements in sample fabrication, the relative role of acoustic phonon scattering must be expected to become increasingly important in future devices.…”

“…The associated deformation potential coupling constant is extracted from the experimentally measured temperature dependence of the resistivity and ranges from ∼18 to 29 eV. 5,[7][8][9]11 On the other hand, theoretical studies of the acoustic electronphonon coupling yield much lower values on the order of 3.9-7.4 eV. [30][31][32] At the same time, different forms of the coupling matrix element are used in theoretical studies 20,32 making a direct comparison of the different values of the deformation potential difficult.…”

Effect of high-κgate dielectrics on charge transport in graphene-based field effect transistors

“…However, suspending graphene by removing the underlying substrate and driving off impurities sticking to it resulted in much higher mobilities near RT, albeit at low carrier concentrations [10][11][12]. When compared to 2D electron gases (2DEGs) in narrow-bandgap III-V semiconductor heterostructures such as InAs and InSb [13], mobilities and low-field conductivities (charge × mobility) in 2D graphene on dielectric substrates reported to date are lower.…”

Probing top-gated field effect transistor of reduced graphene oxide monolayer made by dielectrophoresis

“…Single, bilayer and a few layer graphenes continue to be of immense interest not only for their fascinating physical properties but also for their potential device applications [1][2][3][4][5][6][7]. However bulk processing of single layer graphene and depositing at desirable locations to fabricate devices and sensors are still challenging issues.…”