Hot carrier relaxation of Dirac fermions in bilayer epitaxial graphene
Artikel i vetenskaplig tidskrift, 2015

Energy relaxation of hot Dirac fermions in bilayer epitaxial graphene is experimentally investigated by magnetotransport measurements on Shubnikov-de Haas oscillations and weak localization. The hot-electron energy loss rate is found to follow the predicted Bloch-Gruneisen power-law behaviour of T-4 at carrier temperatures from 1.4K up to similar to 100 K, due to electron-acoustic phonon interactions with a deformation potential coupling constant of 22 eV. A carrier density dependence n(e)(-1.5) in the scaling of the T-4 power law is observed in bilayer graphene, in contrast to the n(e)(-0.5) dependence in monolayer graphene, leading to a crossover in the energy loss rate as a function of carrier density between these two systems. The electron-phonon relaxation time in bilayer graphene is also shown to be strongly carrier density dependent, while it remains constant for a wide range of carrier densities in monolayer graphene. Our results and comparisons between the bilayer and monolayer exhibit a more comprehensive picture of hot carrier dynamics in graphene systems.

hot carriers


energy loss rate

bilayer graphene


J. Huang

University of Oxford

J. A. Alexander-Webber

University of Oxford

Tjbm Janssen

National Physical Laboratory (NPL)

A.Y. Tzalenchuk

National Physical Laboratory (NPL)

Royal Holloway University of London

Thomas Yager

Chalmers, Mikroteknologi och nanovetenskap, Kvantkomponentfysik

Samuel Lara Avila

Chalmers, Mikroteknologi och nanovetenskap, Kvantkomponentfysik

Sergey Kubatkin

Chalmers, Mikroteknologi och nanovetenskap, Kvantkomponentfysik

R. L. Myers-Ward

Naval Research Laboratory

V. D. Wheeler

Naval Research Laboratory

D. K. Gaskill

Naval Research Laboratory

R. J. Nicholas

University of Oxford

Journal of Physics Condensed Matter

0953-8984 (ISSN) 1361-648X (eISSN)

Vol. 27 16 164202

Graphene-Based Revolutions in ICT And Beyond (Graphene Flagship)

Europeiska kommissionen (EU) (EC/FP7/604391), 2013-10-01 -- 2016-03-31.


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