Shot noise and conductivity at high bias in bilayer graphene: Signatures of electron-optical phonon coupling

A. Fay*, R. Danneau, J. K. Viljas, F. Wu, M. Y. Tomi, J. Wengler, M. Wiesner, P. J. Hakonen

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

14 Citations (Scopus)
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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.

Original languageEnglish
Article number245427
Pages (from-to)1-7
Number of pages7
JournalPhysical Review B
Volume84
Issue number24
DOIs
Publication statusPublished - 14 Dec 2011
MoE publication typeA1 Journal article-refereed

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