Influence of carrier screening and impurity correlation on the electron and optical properties of doping superlattices

The theoretical analysis of the electron and optical characteristics of doping superlattices is performed in the case of the Gaussian or exponential distributions in the density state tails and taking into account the electrostatic potential screening and band gap narrowing. The influence of the impurity correlations on the screening lengths and characteristic parameters of the density state tails is considered. It is shown that the impurity correlation leads to a fixed value of the diffusivity-mobility ratio, which at the Gaussian-like tails tends to the classical value kT/e.