EFFECT OF IMPURITIES ON DIPOLE EMISSION RATE IN DOPED PHOTONIC STRUCTURES

We investigate the influence of the foreign impurities on the dipole r elaxation rate in doped n-InP/GaAs superlattice, where (n-InP) has an impurity dependent dielectric function and (GaAs) has a frequency depe ndent dielectric function. We have analysed the dipole rate dependence on the impurity concentration. The results show that the rate decreas es as the impurity concentration is increased towards a critical value , n(c), defining an insulator-metal transition. We have also calculate d how the rate changes with transition frequency w(o). For low concent rations, the rate is reduced for transition frequency w(o) within the band gap. However, for high impurity concentrations this feature is ab sent and the rate is nearly unchanged. This is possibly due to a forma tion of a photonic impurity band within the photonic band gap.