Nonequilibrium carriers in an intrinsic graphene

Abstract

We examine nonequilibrium carriers (electrons and holes) excited by steady-state electric field or mid-IR pumping in an intrinsic graphene at low temperatures. The energy distributions of carriers are calculated using a quasiclassic kinetic equation which accounts for the energy relaxation due to acoustic phonons and the generation-recombination processes associated with thermal radiation. We also discuss the case of acoustic phonons and thermal radiation with different temperatures when nonequilibrium distribution appears due to connection with two thermostats. Using the obtained distributions, we analyze the following responses of nonequilibrium carriers: (a) the current-voltage characteristics of hot carriers, (b) the negative interband absorption, (c) the photoconductivity under a probe dc electric field, and (d) the effect of thermal radiation on conductivity. © 2009 American Institute of Physics.