Limits on Charge Carrier Mobility in Suspended Graphene due to Flexural Phonons

Castro, Eduardo V.; Ochoa, Héctor; Katsnelson, M. I.; Gorbachev, Roman; Elias, D. C.; Новоселов, К. С.; Geǐm, A. K.; Guinea, F.

doi:10.1103/physrevlett.105.266601

Cited by 386 publications

(434 citation statements)

References 29 publications

Supporting

Mentioning

399

Contrasting

Unclassified

Order By: Relevance

“…This value for ρ i is quite close to the results of Ref. 16 on flexural phonon limited mobility in suspended graphene. By interpreting ρ i directly as a scattering length via k f r = h/(4e 2 ρ i ), we find a small value k F r ∼ 7 at T e = 300 K, indicating an effective scattering mechanism activated by the large bias; the subscript r refers to scattering events governing the resistance.…”

supporting

confidence: 90%

“…3 at 0.8 · 10 11 cm 2 (V g = -2.4 V) as a function of T e , with T e determined from the shot noise thermometry. The behavior of R is well fit with a quadratic temperature dependence as expected for flexural phonon scattering 16 . From the fit we obtain R = [1390 + 0.01(T e /K) 2 ] Ω which was employed for determining the pure temperaturedependent part ρ i = 0.01(T e /K) 2 employed in the main text.…”

Section: Details Of the Electrical Characteristicssupporting

confidence: 62%

“…16 Supercollision energy transport is dominated by thermal phonons with q T = k B T / s. Here, s = 2.1 · 10 4 m/s is the speed of the acoustic mode in graphene, and κ = 4.6 · 10 −7 m 2 /s is specified by the dispersion relation of the flexural modes ω = κq 2 . When k F < q * < q T…”

mentioning

confidence: 99%

See 2 more Smart Citations

Electron–Phonon Coupling in Suspended Graphene: Supercollisions by Ripples

et al. 2014

View full text Add to dashboard Cite

Using electrical transport experiments and shot noise thermometry, we find strong evidence that "supercollision" scattering processes by flexural modes are the dominant electron-phonon energy transfer mechanism in high-quality, suspended graphene around room temperature. The power law dependence of the electron-phonon coupling changes from cubic to quintic with temperature. The change of the temperature exponent by two is reflected in the quadratic dependence on chemical potential, which is an inherent feature of two-phonon quantum processes.

show abstract

supporting

confidence: 90%

Section: Details Of the Electrical Characteristicssupporting

confidence: 62%

See 1 more Smart Citation

Electron–Phonon Coupling in Suspended Graphene: Supercollisions by Ripples

et al. 2014

View full text Add to dashboard Cite

show abstract

“…Interestingly, these extracted values of γ match well the experimental γ values recently obtained for fully suspended graphene samples. 30 With this, it is now possible to predict FP-induced limits on CVD SLG's  and R . Fig.…”

Section: Resultsmentioning

confidence: 99%

Quasi-Periodic Nanoripples in Graphene Grown by Chemical Vapor Deposition and Its Impact on Charge Transport

Zheng

Bae³

et al. 2012

ACS Nano

142

137

View full text Add to dashboard Cite

The technical breakthrough in synthesizing graphene by chemical vapor deposition methods (CVD) has opened up enormous opportunities for large-scale device applications. In order to improve the electrical properties of CVD graphene grown on copper (Cu-CVD graphene), recent efforts have focussed on increasing the grain size of such polycrystalline graphene films to 100 micrometers and larger. While an increase in grain size and hence, a decrease of grain boundary density is expected to greatly enhance the device performance, here we show that the charge mobility and sheet resistance of Cu-CVD graphene is already limited within a single grain. We find that the current high-temperature growth and wet transfer methods of CVD graphene result in quasi-periodic nanoripple arrays (NRAs).Electron-flexural phonon scattering in such partially suspended graphene devices introduces anisotropic charge transport and sets limits to both the highest possible charge mobility and lowest possible sheet resistance values. Our findings provide guidance for further improving the CVD graphene growth and transfer process.KEYWORDS CVD graphene, quasi-periodic nanoripple arrays, anisotropic, Charge transport, flexural phonon scattering, transparent electrodes, sheet resistance Graphene 1 is a promising material for many novel device applications such as ultrafast nanoelectronics, optoelectronics and flexible transparent electronics. [2][3][4][5] Cu-based CVD methods have now made wafer-scale graphene synthesis and transfer feasible both for single layer graphene 6,7 (SLG) and bilayer graphene (BLG). 8 This not only brings the commercial applications of graphene within reach, but also provides great advantages in introducing new substrates to enhance and engineer its electronic properties by tuning the substrate-induced screening 9-12 and substrate-induced strain. 13,14 Unlike CVD graphene growth on Ni, 15,16 Cu-CVD graphene growth has a rather weak interaction with the underlying Cu substrate, allowing CVD graphene to grow continuously crossing atomically flat terraces, step edges, and vertices without introducing significant defects. 17 Thus, by controlling pregrowth annealing 7 and fine tuning growth parameters, 18,19 it is now possible to synthesize CVD 3 graphene with sub-millimetre grain size. However, pre-growth annealing and CVD growth typically require high temperatures very close to the melting point of Cu at 1083 ºC. This leads to Cu surface reconstruction and local surface melting 17,20 during graphene growth, making high density Cu singlecrystal terraces and step edges ubiquitous surface features. Taking into account the negative thermal expansion coefficient of graphene, this leads to new surface corrugations in CVD graphene during the cool down process. 21 Previously grain boundaries have been identified as one of the limiting factors to degrade graphene quality. 22 While the heptagon and pentagon network 22,23 at grain boundaries does disrupt the sp 2 delocalization of π electrons in graphene, it remains to be se...

show abstract

“…The extracted series resistances for Sample A are R o−h ≈ 477 ± 53 and R o−e ≈ 944 ± 80 Ω for hole and electron doping, respectively. The difference between R o−h and R o−e is understood as an additional p − n barrier for the electron due to doping from the gold electrodes 14 . For Sample B, we find R o−h = 1563 Ω and R o−e = 812 Ω.…”

mentioning

confidence: 99%

Wiedemann–Franz Relation and Thermal-Transistor Effect in Suspended Graphene

Yigen

Champagne

2013

Nano Lett.

View full text Add to dashboard Cite

We extract experimentally the electronic thermal conductivity, K e , in suspended graphene which we dope using a back-gate electrode. We make use of two-point dc electron transport at low bias voltages and intermediate temperatures (50 -160 K), where the electron and lattice temperatures are decoupled. The thermal conductivity is proportional to the charge conductivity times the temperature, confirming that the Wiedemann-Franz relation is obeyed in suspended graphene. We extract an estimate of the Lorenz coefficient as 1.1 to 1.7 ×10 −8 W ΩK −2 . K e shows a transistor effect and can be tuned with the back-gate by more than a factor of 2 as the charge carrier density ranges from ≈ 0.5 to 1.8 ×10 11 cm −2 .Keywords: Graphene, Thermal conductivity, Wiedemann-Franz, Thermal transistor, electron-phonon Graphene's electronic thermal conductivity, K e , describes how easily Dirac charge carriers (electron and hole quasiparticles) can carry energy. In low-disorder graphene at moderate temperatures (< 200 -300 K), the energy transfer rate between charge carriers and acoustic phonons is extremely slow 1-6 . Thus, K e impacts how a hot electron cools down, and the efficiency of charge harvesting in graphene optoelectronic devices 1,2,7 . Moreover, understanding and controlling K e could help develop graphene bolometers capable of detecting single terahertz photons 4,8 . There are theoretical calculations of K e 9-11 , and recent experimental data near the charge neutrality point (CNP) in clean suspended graphene 6 and in disordered samples at very low temperatures 4,8 . However, a detailed mapping of K e vs charge density at intermediate temperatures is lacking. Understanding how K e in clean (suspended) graphene depends on charge density, n, and the electronic temperature, T e , is crucial for applications. An important fundamental question is whether the Wiedemann-Franz (WF) law, K e = σLT e where σ is the charge conductivity, and L is the Lorenz number, is obeyed in graphene. In clean graphene at low charge densities (hydrodynamic regime), strong electronelectron interactions could lead to departures from the generalized WF law 10,11 .We report K e in monolayer graphene extracted from carefully calibrated dc electron transport measurements following a method we previously discussed 6 . We study a temperature range of T = 50 -160 K, where the electron and lattice temperatures are very well decoupled in low-disorder graphene 1-6 , over a charge density range of ≈ 0.5 to 1.8 ×10 11 cm −2 . We extract data in the hole and electron doped regimes from two high-mobility suspended devices. The extracted K e are compared with predictions from the WF law. The agreement between the WF relation and measurements is very good for both devices over the n range studied and T up to 160 K. The value of L is ≈ 0.5 -0.7 L o , where L o is the Lorenz factor a) Electronic mail: a.champagne@concordia.ca for metals. We observe a sudden jump in the extracted thermal conductivity above 160 K which is consistent with the onset of strong coupling...

show abstract

Limits on Charge Carrier Mobility in Suspended Graphene due to Flexural Phonons

Cited by 386 publications

References 29 publications

Electron–Phonon Coupling in Suspended Graphene: Supercollisions by Ripples

Electron–Phonon Coupling in Suspended Graphene: Supercollisions by Ripples

Quasi-Periodic Nanoripples in Graphene Grown by Chemical Vapor Deposition and Its Impact on Charge Transport

Wiedemann–Franz Relation and Thermal-Transistor Effect in Suspended Graphene

Contact Info

Product

Resources

About