Recombination photoluminescence of nanostructured alumina under VUV excitation

Исследованы процессы фотолюминесценции монокристаллических и наноструктурных оксидных диэлектриков. Разработана физическая модель, созданы алгоритм и программа для моделирования процессов фотолюминесценции с учетом заряжения приповерхностных слоев, процессов переноса, туннельной рекомбинации носителей заряда и особенностей наноструктурного состояния исследуемых образцов оксида алюминия (изменения ширины запрещенной зоны и энергетической глубины ловушек, рассеяния электронов на границах наночастиц, а также изменения ширины линии свечения и времени релаксации возбуждения). Выполнены расчеты указанных процессов, выявлены особенности рекомбинационной фотолюминесценции в наноструктурном образце в сравнении с монокристаллическим аналогом. Получены количественные данные о влиянии размерных зависимостей на спектрально-кинетические свойства исследуемых наноматериалов. Установлены общие закономерности и особенности фотолюминесценции в наноразмерном Al2O3 при различных параметрах возбуждения.The photoluminescence processes of single crystal and nanostructured oxide dielectrics were investigated. The physical model was described; the algorithm and the program were developed for simulating of the photoluminescence taking into account the surface layers charging, transport processes and tunneling recombination of charge carriers, nanocrystalline state features of the alumina samples under investigation (chang in the band gap, energy depth of the traps, emission line width, relaxation time of the excitation and phonon spectrum, the electron scattering at the nanoparticle boundaries). Calculations of these processes were performed; the features of recombination luminescence in nanostructured sample in comparison with single crystal analog were identified. Quantitative data about influence on the size dependence of the spectral and kinetic properties of the nanomaterial under investigation were obtained. General regularities and features of photoluminescence in nanoscale Al2O3 at different excitation parameters are found.Программа развития УрФУ на 2013 год (п.1.2.2.3

TEMPERATURE BEHAVIOR OF THE ABSORPTION EDGE IN BI-IMPLANTED HONGAN SILICA GLASS

The effect of thermal and structural disorder on the electronic structure of glass silicon dioxide (Hongan Silica Glass) irradiated with 30 KeV bismuth ions Φ = 1× 1017 cm-2 is in-vestigated by the McPherson VuVAS 1000PL VUV spectrometer in the 120-500 nm wave-length range

LUMINESCENT AND DOSIMETRIC PROPERTIES OF MAGNESIUM OXIDE CERAMICS WITH AN IMPURITY OF CERIUM

The effect of cerium impurity on the shape of the curve and kinetic parameters of TL of magnesium oxide ceramics obtained in a fast electron beam is revealed

Energy Distribution of Traps in Al2O3-BeO Ceramics

The view of the energy distribution function of traps responsible for the dosimetric ther-moluminescent peak of Al2O3-BeO ceramics is determined. The resulting function is used to explain the anomalous behavior of the thermoluminescence isothermal decay curves in the temperature range of 523–623 K

The fundamentals and applications of density functional theory

В пособии представлены основные понятия теории функционала электронной плотности (ФЭП/DFT). Выделены особенности, обеспечивающие широкое применение данного метода в решении теоретических и прикладных задач физики конденсированного состояния. Учебное пособие предназначено для студентов и аспирантов ФтИ УрФУ, использующих в своей учебной и научной деятельности вычислительные методы.This tutorial introduces the basic concepts behind density functional theory (DFT). The features that provide a wide application of the DFT method in solving theoretical and applied problems of condensed matter physics are highlighted. The manual is intended for students and postgraduates of the FTI UrFU who use computational methods in their educational and scientific activities

Photoluminescence of anion-defective alumina single crystals exposed to high-dose gamma-radiation

The method of UV and VUV spectroscopy with synchrotron radiation was used to measure photoluminescence (PL) spectra and photoluminescence excitation (PLE) spectra in anion-defective alumina single crystals exposed to high doses of gamma-radiation. A change in the intensity of the excitation band of F-centers near the fundamental absorption edge (8.8 eV) was found to depend on doses and temperatures. New wide bands with µs–ms decay kinetics of emission were registered in the PL spectra at excitations with VUV and UV photons. The obtained results show that high-dose irradiations of the crystals under study lead to appearance of F$_{2}$-type aggregate centers in different charged states. These centers are additional traps of charge carriers. Emission bands of other aggregate and impurity centers, which form an experimental PL spectrum in the crystals exposed to high doses, were also identified. The evolution of the centers, produced by oxygen vacancies and impurities, creates the features of dose responses of dosimetric α-Al$_{2}$O$_{3}$:С single crystals exposed to high doses of radiations

Defect evolution and photoluminescence in anion-defective alumina single crystals exposed to high doses of gamma-rays

A method of luminescent UV and VUV spectroscopy was used to study the evolution of color centers in anion-defective alumina single crystals exposed to high doses of gamma-radiation. A sharp drop in the intensity of the emission bands and, therefore, the concentration of F$^{+}$ and F-centers associated with the formation of aggregate F$_{2}$-type centers was found. The aggregate centers create an additional emission band in the range of (1.8–2.8) eV. When the crystals are exposed to middle and high doses, the photoluminescence (PL) intensity is the highest in the emission band of F$_{2}$$^{2+}$-centers, which indicates a high concentration of the aggregates from singly charged oxygen vacancies (of F$^{+}$-centers). When PL of the crystals exposed to high doses is excited with synchrotron radiation of the VUV range, a wide emission band in the red and near infrared (NIR) regions is registered. The centers related presumably to impurity defects, their aggregates and clusters consisting of several oxygen vacancies are responsible for this emission band

LUMINESCENCE OF RADIATION DEFECTS IN Bi IMPLANTED SILICA GLASS

The photoluminescence of silica glass with implanted Bi ions is investigated by lumines-cence spectrometer PerkinElmer LS 55. The goal of the work was to study the optically active defects arising during the implantation process Bi ions in silica glass KUVI

OPTICAL PROPERTIES OF SIO2 GLASSES IMPLANTED WITH BISMUTH IONS

Optically transparent SiO2 glasses were implanted in a pulsed mode with 30 keV bismuth ions with different doses. The depth of penetration of ions into the studied SiO2 samples was estimated using the SRIM software package. Optical absorption spectra were recorded on a Lambda 35 spectrophotometer