Temperature dependence and screening models in quantum cascade structures

Different screening models in quantum cascade lasers are compared by calculating the contribution of intrasubband impurity scattering to the optical linewidth as a function of temperature. We find a strong impact of impurity scattering, which increases substantially with temperature. A simple isotropic bulk screening model works well if the screening length is of the order of or longer than the period length of the cascade structure. (C) 2009 American Institute of Physics. [doi:10.1063/1.3226072]