Comparative analysis of resonant phonon THz quantum cascade lasers

We present a comparative analysis of a set of GaAs-based THz quantum cascade lasers, based on
longitudinal-optical phonon scattering depopulation, by using an ensemble Monte Carlo simulation,
including both carrier-carrier and carrier-phonon scattering. The simulation shows that the parasitic
injection into the states below the upper laser level limits the injection efficiency and thus the device
performance at the lasing threshold. Additional detrimental effects playing an important role are
identified. The simulation results are in reasonable agreement with the experimental findings.