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Wurtzite Zn 1−x Mg x O epilayers (x = 0, 0.26, 0.44, 0.49, 0.66) grown by the plasma-assisted molecular beam epitaxy on ScAlMgO 4 substrate were characterized using the methods of optical spectroscopy: spectroscopic ellipsometry (SE), optical absorption (OA), and photoluminescence (PL). The complex dielectric function in the spectral range of 210–1690 nm, band gap width, exciton absorption and emission parameters, and film quality were studied and discussed. Individual characterization of samples was provided by combining SE and OA measurement results. The observed increase of the band gap up to 4.35 eV with the rise of the MgO content allowed the recommendation of the wurtzite Zn 1−x Mg x O epilayers as material for UV sensors. The origin of defects hampering the practical application of the materials was discussed. [Display omitted] • Wurtzite Zn 1−x Mg x O on ScAlMgO 4 substrate were characterized by optical spectroscopy. • Rise of MgO content causes growth of band gap, exciton absorption and emission energy. • Wide band gap allows application of wurtcite Zn 1−x Mg x O films on SCAM for UV sensors. [ABSTRACT FROM AUTHOR]

The optical properties of aluminum nitride nanotips (AlNNTs) synthesized via vapor transport and condensation process have been studied by cathodoluminescence, photoluminescence (PL), thermoluminescence (TL), and UV absorption measurements. Two defect related transitions around 2.1 and 3.4 eV and an excitonic feature at 6.2 eV were identified. Compared to the AlN macropowders, the AlNNTs showed a blueshift (+0.2 eV) of the ∼3.2 eV peak. Analysis of both PL and TL excitation measurements indicated the existence of subband gap multiple energy levels in AlNNTs. A significant TL intensity even at 145 °C suggests possible ultraviolet detector and dosimetric applications of these AlNNTs. [ABSTRACT FROM AUTHOR]