A theoretical investigation of electron dynamics in superlattice InGaAs/AlInAs quantum cascade lasers (QCLs) is presented, based on a Monte Carlo simulation that includes both electron–electron and electron–phonon scattering. Nonequilibrium phonons and phonon quantization effects have been explicitly considered. Calculated luminescence and gain spectra are presented. Our analysis provides a clear physical insight into the QCL operational mode.

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A theoretical study on the relaxation of coupled free carriers and excitons after non‐resonant optical excitation in bulk wurtzite GaN is presented. In particular the effect of the acoustic piezoelectric scattering is taken under consideration, and the respective rates have been calculated, including screening effects. Results show that the piezo‐acoustic rates are bigger in the wurtzite phase of GaN with respect to the cubic phase, and they are really sensitive to the background doping of the sample. Simulations of the full dynamics of the system are performed by using an Ensemble Monte Carlo method under which all the relevant scattering mechanisms are included. The set of semiclassical Boltzmann equations for electron and hole populations is complemented by an additional equation for the exciton distribution and is coupled by reaction terms describing phonon‐mediated exciton binding and dissociation. The temporal evolution is studied in the short range time (100 ps) after photo‐excitation. It shows that a high background doping prevents the electrons to relax toward low energy states.

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