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

Loading...
Thumbnail Image
Journal Title
Journal ISSN
Volume Title
School of Science | A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Date
2011
Major/Subject
Mcode
Degree programme
Language
en
Pages
245427/1-7
Series
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
Other note
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