Hot carrier and hot phonon coupling during ultrafast relaxation of photoexcited electrons in graphene

Abstract

We study, by means of a Monte Carlo simulator, the hot phonon effect on the relaxation dynamics in photoexcited graphene and its quantitative impact as compared to considering an equilibrium phonon distribution. Our multi-particle approach indicates that neglecting the hot phonon effect significantly underestimates the relaxation times in photoexcited graphene. The hot phonon effect is more important for a higher energy of the excitation pulse and photocarrier densities between $1$ and $3\times 10^{12}{\mathrm{cm}}^{-2}$. Acoustic intervalley phonons play a non-negligible role, and emitted phonons with wavelengths limited up by a maximum (determined by the carrier concentration) induce a slower carrier cooling rate. Intrinsic phonon heating is damped in graphene on a substrate due to additional cooling pathways, with the hot phonon effect showing a strong inverse dependence with the carrier density.

12 pages, 5 figures

References in corpus (5)

• Universal Dynamic Conductivity and Quantized Visible Opacity of Suspended Graphene
• Dielectric function, screening, and plasmons in 2D graphene
• Acoustic phonon scattering limited carrier mobility in 2D extrinsic graphene
• Cooling of photoexcited carriers in graphene by internal and substrate phonons
• Influence of the substrate on the diffusion coefficient and the momentum relaxation in graphene: the role of surface polar phonons

Cited by in corpus (8)

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• Modulation characteristics of uncooled graphene photodetectors
• Non-equilibrium electron relaxation in Graphene
• On the interpretation of manifold ultrafast dynamics in supported graphene
• Planar phonon anisotropy, and a way to detect local equilibrium temperature in graphene