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Heteroepitaxial ZnxMg1−xO thin films were grown on lattice-matched MgO (100) substrates using radiofrequency plasma-assisted molecular-beam epitaxy. High-quality epilayers with zinc concentrations ranging from x = 0 (MgO) to x = 0.65 were grown and characterized optically, structurally, and electrically. The ZnxMg1−xO films were found to maintain the rocksalt cubic (B1) crystal structure for concentrations z < 0.65, with a linear dependence of lattice constant on Zn concentration. X-ray diffraction (XRD) also revealed the emergence of phase segregation into wurtzite (B4) phase for the highest concentration film. The band gap energy of the films was successfully varied from 4.9 to 6.2 eV (253–200 nm), showing a linear relationship with Zn concentration. The strictly cubic films exhibit roughness on the order of 10 Å and resistivities of approximately 106 Ω·cm.

The complex refractive indices of Cd x Zn1−x O thin films were determined by transmission spectrophotometry. Transmission spectra were modeled from 375 nm to 800 nm for samples having cadmium concentrations ranging from 2% to 77%. The transparent and absorptive regimes were fitted separately by Sellmeier and Forouhi–Bloomer models, respectively. Real refractive indices of Cd x Zn1−x O shift to higher values in the transparent region and the optical absorption edge shifts to longer wavelengths with increasing cadmium concentration. Spectroscopic ellipsometry was carried out on one sample from λ = 190 nm to 1.8 µm. Comparison between the two methods shows that the results are in general agreement.

Trace uncontrolled impurities as Ce3+, Cr3+, Eu3+ and Nd3+ were detected in YAlO3 and YAlO3: Cr crystals from their fluorescence by high sensitive photon counting detection. The concentrations of Ce, Cr, Eu, Nd and some other impurities (Tm, Ho, Mn, Mg, Fe) were also determined by electron beam excited X-ray microanalysis (abbr. EMA) in YAlO3 and Y3Al5O12 crystals (pure or doped). Both the methods (fluorescence detection and EMA) are compared, fluorescence properties of some trace impurities were determined and their influence on local distribution and transfer processes (Ce3+→Nd3+, Cr3+→ Nd3+) in these crystals are discussed.