Influence of the ZnTe barrier width on photoluminescence spectra of CdTe/ZnTe superlattices with layers of quantum dots

The photoluminescence and Raman spectra of CdTe/ZnTe superlattices with layers of CdTe quantum dots have been measured in the temperature range of 5–85 K. It has been found that, in the photoluminescence spectra, there are three emission bands, which are attributed to the luminescence of two-dimensional wetting layers, direct excitons, and spatially indirect excitons in quantum dots, respectively. The influence of the width of the ZnTe barrier layer in the range of 2–50 ML on the energy and width of the emission lines of quantum dots and wetting layer has been analyzed. The temperature dependences of the photoluminescence intensity of direct and indirect excitons have been investigated and the corresponding activation energies of temperature quenching of luminescence have been determined.