The ESR spectra of nanostructured samples of monoclinic ZrO₂ irradiated by electrons with energies of 130 keV, 10 MeV, and by a beam of Xe ions (220 MeV) have been studied. It has been established that irradiation of samples with electrons (10 MeV) and ions leads to the formation of radiation-induced F⁺ centers in them. Thermal destruction of these centers is observed in the temperature range of 375–550 K for electron-irradiated and 500–700 K for ion-irradiated samples. It is shown that the decrease in the concentration of F⁺ centers is associated with the emptying of traps responsible for thermoluminescence (TL) peaks in the specified temperature range. In the samples irradiated with an ion beam, previously unidentified paramagnetic centers with g = 1.963 and 1.986 were found, the formation of which is likely to involve Zr³⁺ ions and oxygen vacancies. Thermal destruction of these centers occurs in the temperature range from 500 to 873 K.

The use of CH₄ as an energy source is increasing every day. To increase the efficiency of CH₄ combustion and ensure that the equipment meets ecological requirements, it is necessary to measure the CH₄ concentration in the exhaust gases of combustion systems. To this end, sensors are required that can withstand extreme operating conditions, including temperatures of at least 600 °C, as well as high pressure and gas flow rate. ZnGa₂O₄, being an ultra-wide bandgap semiconductor with high chemical and thermal stability, is a promising material for such sensors. The synthesis and investigation of the structural and CH₄ sensing properties of ceramic pellets made from pure and Er-doped ZnGa₂O₄ were conducted. Doping with Er leads to the formation of a secondary Er₃Ga₅O₁₂ phase and an increase in the active surface area. This structural change significantly enhanced the CH₄ response, demonstrating an 11.1-fold improvement at a concentration of 10⁴ ppm. At the optimal response temperature of 650 °C, the Er-doped ZnGa₂O₄ exhibited responses of 2.91 a.u. and 20.74 a.u. to 100 ppm and 10⁴ ppm of CH₄, respectively. The Er-doped material is notable for its broad dynamic range for CH₄ concentrations (from 100 to 20,000 ppm), low sensitivity to humidity variations within the 30–70% relative humidity range, and robust stability under cyclic gas exposure. In addition to CH₄, the sensitivity of Er-doped ZnGa₂O₄ to other gases at a temperature of 650 °C was investigated. The samples showed strong responses to C₂H₄, C₃H₈, C₄H₁₀, NO_2, and H₂, which, at gas concentrations of 100 ppm, were higher than the response to CH₄ by a factor of 2.41, 2.75, 3.09, 1.16, and 1.64, respectively. The study proposes a plausible mechanism explaining the sensing effect of Er-doped ZnGa₂O₄ and discusses its potential for developing high-temperature CH₄ sensors for applications such as combustion monitoring systems and determining the ideal fuel/air mixture.

Samples of ZrO₂ ceramics with different concentrations of impurity titanium ions were synthesized by mixing zirconium and titanium oxide powders in different mass ratios. The X-ray diffraction analysis was used to determine the phase composition, lattice parameters, and crystallite size of the ceramics with varying dopant concentrations. Upon irradiation of the samples with 220 MeV Xe ions to a fluence of 10¹⁰ ions/cm², a decrease in the intensity of the pulsed cathodoluminescence band at 2.5 eV was observed. Additionally, ion irradiation resulted in the emergence of a new thermoluminescence peak at 450–650 K attributed to radiation-induced traps of charge carriers. Further analysis revealed that the thermoluminescence curves of samples irradiated with electrons and ions comprise a superposition of several elementary peaks. Notably, a complex non-monotonic dependence of cathodo- and thermoluminescence intensity on titanium concentration was observed, suggesting the influence of concentration quenching and the presence of tunneling transitions.

Samples of ZrO2 ceramics with different concentrations of impurity titanium ions were synthesized by mixing powders of zirconium and titanium oxides in various mass ratios. The phase composition and surface morphology of the studied ceramics were determined by X-ray phase analysis and scanning electron microscopy. It was found that irradiation of samples with xenon ions (220 MeV) with fluences 1010 and 1012 ion/cm2 leads to a decrease in the intensity of the pulse cathodoluminescence band at 2.5 eV. It is shown that ion irradiation causes the appearance of a new peak of thermoluminescence at 450-650 K of a non-elementary form associated with radiation-induced traps of charge carriers. In contrast to electron irradiation, an increase in the fluence of ions leads to a decrease in the intensity of this peak. In contrast to electron irradiation, an increase in the fluence of ions leads to a decrease in the intensity of this peak. A complex nonmonotonic dependence of the cathode and thermoluminescence intensity on the dopant concentration was found, which may be due to the effects of concentration quenching and aggregation of defective centers.

The photoluminescence (PL) and photoluminescence excitation (PLE) spectra of an EFG-grown (−201) β-Ga₂O₃ single crystal were recorded at 7 and 300 K at the FinEstBeAMS beamline of the MAX IV Laboratory. Excitation–emission maps and fixed-wavelength PLE profiles covered 4.50–10.50 eV at both temperatures. Each temperature series was normalized to its own 5.00 eV intensity and, alternatively, to its own maximum; the reported ratios therefore describe excitation dependence within one series and not an absolute difference in luminescence yield between temperatures. At 7 K, integrated emission at 10.50 eV retains 95.4% of its 5.00 eV value and 89.2% of its maximum. At 300 K, the PLE half-height is 4.55 eV, and the maximum occurs at 4.75–4.80 eV, followed by a decrease to 2.26% of the 5.00 eV value and 2.03% of the maximum at 10.50 eV. Room-temperature ellipsometry on the same factory-polished face places the PLE rise in the rapidly increasing absorption region and yields a penetration depth of approximately 0.24 μm near the PLE half-height and 37 nm at 5.90 eV. A constrained depth-dependent calculation does not reproduce the full decline, so surface capture is retained as one possible pathway rather than an established mechanism. The emission is described by the same effective bands at 3.55, 3.37 and 3.07 eV used in the preceding laser study. Their balance is nearly constant at 7 K, whereas the low-energy spectral weight increases at 300 K under deep-VUV excitation. These spectra provide quantitative reference profiles for energy conversion and carrier capture in β-Ga₂O₃.