Hot carriers in graphene

Hot carrier diffusion in graphene

We report an optical study of charge transport in graphene. Diffusion of hot carriers in epitaxial graphene and reduced graphene-oxide samples are studied using an ultrafast pump-probe technique with a high spatial resolution. Spatiotemporal dynamics of hot carriers after a pointlike excitation are monitored. Carrier-diffusion coefficients of 11 000 and 5500 cm2 s−1 are measured in epitaxial gr...

Evidence for extraction of photoexcited hot carriers from graphene.

We report evidence of nonequilibrium hot carrier extraction from graphene by gate-dependent photocurrent study. Scanning photocurrent excited by femtosecond pulse laser shows unusual gate dependence compared with continuous wave (CW) laser excitation. Power dependence studies further confirm that the photocarriers extracted at the metal/graphene contact are nonequilibrium hot carriers. Hot carr...

Hot carriers in graphene

Hot carriers in graphene

Cooling of photoexcited carriers in graphene by internal and substrate phonons

We investigate the energy relaxation of hot carriers produced by photoexcitation of graphene through coupling to both intrinsic and remote (substrate) surface polar phonons using theBoltzmann equation approach.Wefind that the energy relaxation of hot photocarriers in graphene on commonly used polar substrates, under most conditions, is dominated by remote surface polar phonons. We also calculat...