Coupled carrier-field Monte-Carlo analysis of mid-IR quantum cascade lasers

A short-injector mid-infrared quantum cascade laser based on the In_0.6Ga_0.4As/In_0.365Al_0.635As material system is analyzed by means of a self-consistent ensemble Monte-Carlo method. Scattering mechanisms, namely electron - acoustic phonon, electron-longitudinal optical phonon including hot phonons, electron-electron, electron-alloy, electron-impurity and interface roughness scattering as well as the interaction with the cavity field are self-consistently included and are discussed based on their relevance. We get good agreement with experiment, validating our approach. We find that the output power of such devices is limited by scattering with LO phonons, and to a smaller extend also by interface roughness scattering as well as alloy disorder.