Shot noise and conductivity at high bias in bilayer graphene: Signatures of electron-optical phonon coupling
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© 2011 American Physical Society (APS). This is the accepted version of the following article: Fay, A. & Danneau, R. & Viljas, J. K. & Wu, F. & Tomi, M. Y. & Wengler, J. & Wiesner, M. & Hakonen, Pertti J. 2011. Shot noise and conductivity at high bias in bilayer graphene: Signatures of electron-optical phonon coupling. Physical Review B. Volume 84, Issue 24. 245427/1-7. ISSN 1098-0121 (printed). DOI: 10.1103/physrevb.84.245427, which has been published in final form at http://journals.aps.org/prb/abstract/10.1103/PhysRevB.84.245427.
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A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
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Date
2011
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Degree programme
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en
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245427/1-7
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Physical Review B, Volume 84, Issue 24
Abstract
We have studied electronic conductivity and shot noise of bilayer graphene (BLG) sheets at high bias voltages and low bath temperature T0=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 τe–op. In a 230-nm-long BLG sample of mobility μ=3600 cm exp 2 exp V−1 s exp −1, we find that τe–op decreases with increasing voltage and is close to the charged impurity scattering time τimp=60 fs at V=0.6 V.Description
Keywords
field-effect transistors, quantum transport, carbon nanotubes, chaotic cavities, scattering, devices, states, suppression
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Citation
Fay, A. & Danneau, R. & Viljas, J. K. & Wu, F. & Tomi, M. Y. & Wengler, J. & Wiesner, M. & Hakonen, Pertti J. 2011. Shot noise and conductivity at high bias in bilayer graphene: Signatures of electron-optical phonon coupling. Physical Review B. Volume 84, Issue 24. 245427/1-7. ISSN 1098-0121 (printed). DOI: 10.1103/physrevb.84.245427