The main purpose of this work was to carry out a low-temperature synthesis of glass ceramics containing YNbO4:Eu3+ crystallites and to study the structural and luminescent properties of the obtained samples. Within the framework of this work, the inclusions that crystallized under the conditions of low-temperature synthesis in the systems of SiO2-Na2O-K2O-Y2O3-Nb2O5-Eu2O3 (SiNaK) and B2O5-Na2O-Y2O3-Nb2O5-Eu2O3 (BNa) were investigated for the first time. It was shown that YNbO4: Eu3+ crystallized in both considered systems. In the SiNaK system the crystallization of SiO2 also occurred (quartz, crisstabolite, and tridymite) under the selected conditions. The BNa system proved to be the most promising for the synthesis of activated glass-ceramics with YNbO4, since the required crystallites crystallized only in ithis system. The luminescent properties of crystalline inclusions were investigated using the local cathodoluminescence technique. The composition and structure of glass ceramics were studied by electron-probe microanalysis and X-ray diffraction phase analysis.
During the study of materials on electron probe devices in the field of the electron beam, a contamination hydrocarbon film is formed, which influences the results of experiments. In this paper, we studied the effect of a contamination film formed on carbon-coated dielectric samples on the intensity of cathodoluminescence and X-ray characteristic emission lines. The absorption coefficient of the film for the visible and UV ranges was determined. The mechanism of film formation for various parameters of the electron beam is discussed.
The dependence of the conductivity of the films of hafnium oxide HfO_2 synthesized in different modes is studied. Depending on the modes of synthesis, the conductivity of HfO_2 at a fixed electric field of 1.0 MV/cm changes by four orders of magnitude. It is found that the conductivity of HfO_2 is limited by the model of phonon-assisted tunneling between the traps. The thermal and optical energies of the traps W _t = 1.25 eV and W _opt = 2.5 eV, respectively, in HfO_2 are determined. It is found that the exponentially strong scattering of the conductivity of HfO_2 is due to the change in the trap density in a range of 4 × 10^19–2.5 × 10^22 cm^–3. In the cathodoluminescence spectra of HfO_2, a blue band with the energy of 2.7 eV is observed which is due to the oxygen vacancies. A correlation between the trap density and intensity of cathodoluminescence, as well as between the trap density and refractive index, is found. A nondestructive in situ method for the determination of the trap density of hafnium oxide with the use of the measurement of the refractive index is proposed. The optimum values of the concentrations of oxygen vacancies for emitting devices on the basis of the films of HfO_2 are found.
Методами локальной катодолюминесценции и рентгеноспектрального микроанализа проведено комплексное исследование широкозонных наногетероструктур на основе ZnSe, полученных методом молекулярно-пучковой эпитаксии. Было показано, что используемые методы позволяют неразрушающим способом определять глубину залегания, элементный состав и геометрические параметры наноразмерного слоя ZnCdSe. Точность результатов контролировалась методом просвечивающей электронной микроскопии. Методики исследования основаны на возможности варьирования энергии первичного электронного пучка, что приводит к изменению областей генерации характеристического рентгеновского излучения и катодолюминесценции. DOI: 10.21883/FTP.2017.01.8249
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