Abstract
We investigate the influence of the foreign impurities on the dipole relaxation rate in doped n-InP/GaAs superlattice, where (n-InP) has an impurity dependent dielectric function and (GaAs) has a frequency dependent dielectric function. We have analysed the dipole rate dependence on the impurity concentration. The results show that the rate decreases as the impurity concentration is increased towards a critical value, n(c), defining an insulator-metal transition. We have also calculated how the rate changes with transition frequency w(o). For low concentrations, the rate is reduced for transition frequency w(o) within the band gap. However, for high impurity concentrations this feature is absent and the rate is nearly unchanged. This is possibly due to a formation of a photonic impurity band within the photonic band gap.