Intra-center excitation dynamics in Cd0.6Mn0.4Te/Cd0.5Mg0.5Te superlattices and Cd0.5Mn0.5Te thin film

Intra-center luminescence dynamics has been investigated under low excitation density in Cd0.6Mn0.4Te/Cd0.5Mg0.5Te superlattices and Cd0.5Mn0.5Te thin film both experimentally and by Monte-Carlo simulation. A model developed earlier by the author for bulk Cd1-xMnxTe is applied to the superlattices with quantum wells of different width. It was demonstrated that under low temperature hopping-assisted quenching has been neglected in distinct of the significant quenching which was previously stated in bulk samples. In the superlattices with narrower quantum wells a homogeneous broadening is stated to be remarkably enhanced. To make clear an origin of the enhancement more experimental data are required. Noticeable non-exponential decay in Mn2+-luminescence transients is explained by stochasticity in decay rates, which are found to be completely correlated with the ions' energies. Partial correlation is stated to take place for the Mn2+-ions' energies of T-4(1)- and T-4(2)-states participating in the excitation process. The correlation loss is claimed to be originated from symmetry breakdown. Validity of the model applied to the superlattices is proved by good agreement of the experimental data and calculations under temperature rise from 13 to 77 K. (C) 2013 Elsevier B.V. All rights reserved.