Effect of ZnTe buffer layer on the structural and optical properties of CdTe/ZnTe quantum dots

We have studied growth of self-assembled CdTe quantum dots (QDs) grown on various thicknesses of ZnTe buffer layer by using molecular beam epitaxy (MBE) and atomic layer epitaxy (ALE). The excitonic peak corresponding to the interband transitions from the ground electronic subband to the ground heavy-hole band (E₁-HH₁) in the CdTe/ZnTe QDs shifted to a lower energy with increasing thickness of the ZnTe buffer layer. The results of the atomic force microscopy (AFM) images showed that the size of the CdTe/ZnTe QDs increases with increasing thickness of the ZnTe buffer layer. The activation energy of the electrons confined in the CdTe/ZnTe QDs, as obtained from the temperature-dependent PL spectra, increases with increasing thickness of the ZnTe buffer layer. These results can help improve our understanding of the effect of the ZnTe buffer layer on the structural and the optical properties of CdTe/ZnTe QDs.