Electron-impurity scattering rate in doped bilayer graphene

2012 ◽  
Author(s):  
Digish K. Patel ◽  
A. C. Sharma
Keyword(s):  
Impurity Scattering ◽  
Bilayer Graphene ◽  
Scattering Rate

Temperature Dependence Electron-Impurity Scattering Rate in Doped Bilayer Graphene

2013 ◽  
Vol 665 ◽  
pp. 154-158
Author(s):  
Digish K. Patel ◽  
K.N. Vyas ◽  
A.C. Sharma
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Single Layer ◽  
Impurity Scattering ◽  
Temperature Limit ◽  
Bilayer Graphene ◽  
Particle Energy ◽  
Experimental Result ◽  
High Temperature Limit ◽  
Scattering Rate

Apart from its promising new material for technological innovations and applications, graphene offers a new and novel physics. In recent past, both single layer and bilayer Graphene have extensively been studied. Properties of Graphene sharply differ from that of 2DEG observed in doped semiconductor heterostructures. One of the important properties requisite for device making is charge transport. It has been suggested that considering a scattering mechanism based on screened charged impurities, one can obtain from a Boltzmann equation approach a conductivity that agrees with the experimental result on graphene. In this paper, we present a calculation of electron-impurity scattering rate, as a function of quasi particle energy ε measured from Fermi energy εf, in doped bilayer graphene for both high temperature TTf and low temperature TTf regimes. In the low temperature limit, we observe dip at normalized energy y=1.0, which is absent in the high temperature limit. Our numerical calculation shows that scattering rate remains almost constant with temperature in both regimes.

scholarly journals Charged impurity scattering in bilayer graphene

2010 ◽  
Vol 82 (4) ◽  
Author(s):  
Shudong Xiao ◽  
Jian-Hao Chen ◽  
Shaffique Adam ◽  
Ellen D. Williams ◽  
Michael S. Fuhrer
Keyword(s):  
Impurity Scattering ◽  
Bilayer Graphene ◽  
Charged Impurity ◽  
Charged Impurity Scattering

Comparative Analysis of λ≈9µm GaAs/AlGaAs Quantum Cascade Lasers with Different Injector Doping

2006 ◽  
Vol 518 ◽  
pp. 29-34
Author(s):  
D. Indjin ◽  
S. Höfling ◽  
A. Mirčetić ◽  
V.D. Jovanović ◽  
J. Radovanović ◽  
...  
Keyword(s):  
Comparative Analysis ◽  
Quantum Cascade Lasers ◽  
Optical Power ◽  
Impurity Scattering ◽  
Resonance Structure ◽  
Quantum Cascade ◽  
Scattering Rate ◽  
Current Saturation ◽  
Single Temperature ◽  
Cascade Lasers

An experimental and theoretical comparative analysis of the output characteristics of λ ≈ 9m GaAs/Al0.45Ga0.55As quantum cascade lasers based on single and double phonon resonance depopulation mechanisms were presented. The layer structures were grown with solid source molecular beam epitaxy and consist of 48 or 36 active stages embedded in a symmetrical plasmon enhanced waveguide. From the wafers, ridge waveguide lasers were fabricated by optical lithography and dry etching. The theoretical model is based on a fully non-equilibrium Schrödinger- Poisson self-consistent analysis of the coupled scattering rate and single-temperature energy balance equations, taking all relevant electron-LO phonon, electron-electron and electron-ionised impurity scattering processes into account. Single phonon resonance devices exhibit clear current saturation, simultaneously with a decrease of the optical power. In the moderate doping regime, a quasi-linear dependence of both the threshold and saturation current densities on injector doping, were measured, in a very good agreement with theoretical predictions. Double phonon resonance lasers exhibit ‘saturation’ mechanism evident from their decrease in optical power, but without pronounced current saturation. Previously reported saturation of the ‘maximal’ current under higher injector doping in single phonon resonance lasers, is also observed in the double phonon resonance structure for injector sheet doping above 8x1011cm-2.

ELECTRON-IMPURITY SCATTERING IN DOPED SINGLE LAYER GRAPHENE

2013 ◽  
Vol 27 (05) ◽  
pp. 1350033
Author(s):  
DIGISH K. PATEL ◽  
A. C. SHARMA ◽  
S. S. Z. ASHRAF
Keyword(s):  
Fermi Energy ◽  
Transport Theory ◽  
Single Layer ◽  
Impurity Scattering ◽  
Single Layer Graphene ◽  
Boltzmann Transport ◽  
Layer Graphene ◽  
Scattering Rate ◽  
Boltzmann Transport Theory ◽  
Dimensional Electron Gas

We calculated electron-impurity scattering rate (ℏ/τ) as a function of quasiparticle energy (ε) for doped single layer graphene (SLG), bilayer graphene (BLG) and two-dimensional electron gas (2DEG) at zero temperature. (ℏ/τ) of SLG has been computed analytically as well as numerically. Computed results show that ℏ/τ of SLG; (a) tends to zero at ε = 0 and, (b) it exhibits peak at ≈1.6εf, where εf is Fermi energy. Contrary to this, ℏ/τ of 2DEG and BLG show their maximum values at ε = 0 and decline thereafter on increasing ε to attain a minimum at around ε equal to Fermi energy. We thus find that ℏ/τ versus ε of SLG displays an entirely different behavior than that of BLG and 2DEG, suggesting that electron-impurity scattering process in SLG sharply differs from those in BLG and 2DEG. Further, computed ℏ/τ of SLG exhibits a large variation in its magnitude over the energy range of 0 ≤ ε ≤ 3εf. Estimation of resistivity within Boltzmann transport theory involves an scattering rate averaged over all possible values of ε. It can therefore be inferred that the computation of resistivity with the use of ℏ/τ at ε = εf for comparing the computed results with experimental data can be highly misleading. Scattering rates of SLG, BLG and 2DEG are found increasing on enhancing the impurity concentration.

scholarly journals Transport and Elastic Scattering Times as Probes of the Nature of Impurity Scattering in Single-Layer and Bilayer Graphene

2010 ◽  
Vol 104 (12) ◽  
Author(s):  
M. Monteverde ◽  
C. Ojeda-Aristizabal ◽  
R. Weil ◽  
K. Bennaceur ◽  
M. Ferrier ◽  
...  
Keyword(s):  
Elastic Scattering ◽  
Single Layer ◽  
Impurity Scattering ◽  
Bilayer Graphene
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