The effect of both CuO content (1 and 8 mol%) and calcination temperature (T c = 500-1000 • C) on light emitting and structural properties of ZrO 2 -Y 2 O 3 -CuO nanopowders was studied by photoluminescence (PL), X-ray diffraction (XRD) and Raman scattering methods. The samples, calcinated at T c = 500-700 • C, contain the tetragonal ZrO 2 phase predominantly. The increase of T c results in its transformation to monoclinic one, and the phase transformation happens at higher temperature at higher Cu content. It is shown that the increase of T c from 500 to 800 • C results in the Cu incorporation into nanocrystals from the surface entities. This manifests itself in the shift of XRD and Raman peaks of tetragonal phase. The PL spectra demonstrate the presence of two main PL components peaked at about 540 nm and 630 nm in the most samples. The increase of T c from 500 to 1000 • C results in the non-monotonic variation of total PL intensity as well as in minor changes in PL spectra shape. The evolution of PL intensity is explained by both the increase of a crystallinity degree and the variation of the concentration of non-radiative recombination centres. The transformation of PL spectra shape is ascribed to the appearance of radiative Cu Zr centres.

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Optical properties of single-layer and multistack CdSe/ZnSe self-assembled quantum dot (QD) heterostructures have been investigated. It is found that QDs at the interface can accumulate cation vacancy-related defects. In this case the level of defects is associated with the quantized heavy-hole level of the QDs. It is shown that study of the excitation spectra of the defect-related band enables one to obtain information about optical transitions in QDs.

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