Microscopic modelling of semiconductor-based quantum devices: a predictive simulation strategy

We review and discuss the first fully three-dimensional study of non-equilibrium carrier dynamics governing semiconductor-based intersubband optoelectronic devices like, e.g., quantum-cascade lasers. First, a multisubband Monte Carlo simulation scheme in a kinetic Boltzmann-like approach is presented. Then, its generalisation into a density-matrix quantum-transport formalism is discussed. This allows us to directly access microscopic key-features of the electron relaxation dynamics (without resorting to phenomenological parameters) as well as to investigate the nature, coherent vs incoherent, of charge injection/transport processes. Besides providing a quantitative investigation into the operation of these devices, our kinetic analysis can indeed serve as a predictive tool for the evaluation of new designs and strategies. Applications are presented concerning quantum-cascade devices, both state-of-the-art mid-infrared lasers as well as novel Thz emitters.