Carrier-phonon scattering in the optoelectronic response of laser-generated electron-hole plasmas in a GaAs nanowire

We examine the role of carrier-phonon scattering in the ultrafast optoelectronic response of a subwavelength a GaAs nanowire.  The wire is exposed to a low bias voltage when it is excited by an ultrashort resonant laser pulse.  For low bias voltages resulting in DC fields less than 0.6 kV/cm within the nanowire, the laser-excited carrier distributions reach a quasi-equilibrium within 100 ps, from which we calculate a stable conductivity that is nonlinear with the applied DC field.  At higher DC field strengths, phonons do not contain the carrier distributions near the gamma-point.  Instead, they break free and traverse the band structure. Further calculations including Coulomb scattering and dephasing show that these effects are not negligible for these high DC field cases once the carrier distributions reach higher energies.  We also confirm that Coulomb scattering and dephasing are safely negligible for the low DC field cases.