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Hot carrier relaxation of Dirac fermions in bilayer epitaxial graphene

J. Huang ; J. A. Alexander-Webber ; T. Janssen ; A. Tzalenchuk ; Thomas Yager (Institutionen för mikroteknologi och nanovetenskap, Kvantkomponentfysik) ; Samuel Lara-Avila (Institutionen för mikroteknologi och nanovetenskap, Kvantkomponentfysik) ; Sergey Kubatkin (Institutionen för mikroteknologi och nanovetenskap, Kvantkomponentfysik) ; R. L. Myers-Ward ; V. D. Wheeler ; D. K. Gaskill ; R. J. Nicholas
Journal of Physics: Condensed Matter (0953-8984). Vol. 27 (2015), 16,
[Artikel, refereegranskad vetenskaplig]

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.

Nyckelord: hot carriers, bilayer graphene, energy loss rate, magnetotransport

Denna post skapades 2015-06-02. Senast ändrad 2015-12-17.
CPL Pubid: 217924


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Denna publikation är ett resultat av följande projekt:

Graphene-Based Revolutions in ICT And Beyond (GRAPHENE) (EC/FP7/604391)