Hot carriers in an intrinsic graphene

TL;DR

This paper investigates the behavior of hot carriers in intrinsic graphene under electric fields, analyzing energy relaxation, generation-recombination processes, and resulting nonlinear current-voltage characteristics.

Contribution

It provides a detailed analysis of nonequilibrium carrier distributions and nonlinear electrical responses considering both intraband and interband processes in graphene.

Findings

Low threshold for nonlinear response in graphene.

Appearance of a second ohmic region at high fields.

Nonlinear current-voltage characteristics calculated for elastic scattering.

Abstract

Heating of carriers in an intrinsic graphene under dc electric field is considered taking into account the intraband energy relaxation due to acoustic phonon scattering and the interband generation-recombination transitions due to thermal radiation. The distribution of nonequilibrium carriers is obtained for the cases when the intercarrier scattering is unessential and when the carrier-carrier Coulomb scattering effectively establishes the quasiequilibrium distribution with the temperature and the density of carriers that are determined by the balance equations. Because of an interplay between weak energy relaxation and generation-recombination processes a very low threshold of nonlinear response takes place. The nonlinear current-voltage characteristics are calculated for the case of the momentum relaxation caused by the elastic scattering. Obtained current-voltage characteristics show low threshold of nonlinear behavior and appearance of the second ohmic region, for strong fields.