Model calculation of the laser-semiconductor interaction in subpicosecond regime

Hot Carrier Relaxation by Extreme Electron-LO Phonon Scattering in GaN

“…The electron injection and phonon replica peaks persist for times greater than 1 ps, which is not observed in our experiments. This effect has also been observed in other hot-carrier models which do not consider excitonic effects [6].…”

Nonequilibrium hole relaxation dynamics in an intrinsic semiconductor

“…25 These are expected to only weakly alter the measured signal for the carrier densities (у2ϫ10 16 cm Ϫ3 ) and high-energy carrier states investigated here. The nonequilibrium distributions are described by the wave-vector-dependent occupation numbers, f i , of the different bands whose time evolutions are computed by numerically solving the carrier Boltzmann equations:…”

“…Assuming isotropic parabolic bands ͑with effective masses m e ϭ0.066m 0 , m HH ϭ0.5m 0 , m LH ϭ0.082m 0 ) and neglecting the transient k-space anisotropy of the carrier distributions, 2,6 the occupation numbers only depend on the carrier energy, which greatly simplifies resolution of the above system, 25,26 making it manageable on a personal computer. The carrier-carrier scattering rates are identical to those extensively discussed by many authors, 25,[27][28][29][30] neglecting the exchange term, and will not be explicitly given here. For scattering processes involving holes, the zone center hole wave function overlap integrals calculated by Wiley 31 have been taken into account in the Coulomb matrix elements.…”

“…22,30 However, this contribution does not play an essential role here since the photoexcited electrons exchange little energy with LO phonons to thermalize. For the same reason, the nonequilibrium phonon effect due to electron-phonon interactions 25,28 has been neglected.…”

Large inherent optical gain from the direct gap transition of Ge thin films

“…The broader energy distribution of non-equilibrium electrons can lead to a broader gain spectrum at the cost of a lower peak gain according to nonequilibrium statistical mechanics. 24 For n þ Ge, the inherent direct gap gain is 25Â greater than the steady-state optical gain with similar injected carrier density since only a few percent of injected electrons occupy the direct C in the latter case. 5 An implication of this study is that if we could reduce the C!L (directto-indirect) intervalley scattering rate, or conversely, enhance the L!C (indirect-to-direct) intervalley scattering, then a much higher steady-state optical gain can be achieved for more efficient Ge CW lasers.…”