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Shot noise and conductivity at high bias in bilayer graphene: Signatures of electron-optical phonon coupling
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A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
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en
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7
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Physical Review B, Volume 84, issue 24, pp. 1-7
Abstract
We have studied electronic conductivity and shot noise of bilayer graphene (BLG) sheets at high bias voltages and low bath temperature T 0=4.2 K. As a function of bias, we find initially an increase of the differential conductivity, which we attribute to self-heating. At higher bias, the conductivity saturates and even decreases due to backscattering from optical phonons. The electron-phonon interactions are also responsible for the decay of the Fano factor at bias voltages V>0.1 V. The high bias electronic temperature has been calculated from shot-noise measurements, and it goes up to ∼1200 K at V=0.75 V. Using the theoretical temperature dependence of BLG conductivity, we extract an effective electron-optical phonon scattering time τ e-op. In a 230-nm-long BLG sample of mobility μ=3600 cm2V -1s -1, we find that τ e-op decreases with increasing voltage and is close to the charged impurity scattering time τ imp=60 fs at V=0.6 V.
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Fay, A, Danneau, R, Viljas, J K, Wu, F, Tomi, M Y, Wengler, J, Wiesner, M & Hakonen, P J 2011, 'Shot noise and conductivity at high bias in bilayer graphene : Signatures of electron-optical phonon coupling', Physical Review B, vol. 84, no. 24, 245427, pp. 1-7. https://doi.org/10.1103/PhysRevB.84.245427