Thermal stability of color centers in LiF crystals: dependence on radiation type and dose

Accumulation of radiation defects at irradiation is the complex result of consecutive and mutually independent events: formation of primary pair, spatial separation of its components and their transformation into stable ones under experimental conditions [1]..

Thermal stability of color centers in LiF crystals: dependence on radiation type and dose

Accumulation of radiation defects at irradiation is the complex result of consecutive and mutually independent events: formation of primary pair, spatial separation of its components and their transformation into stable ones under experimental conditions [1]..

Transition levels of acceptor impurities in ZnO crystals by DFT-LCAO calculations

This research was partly supported by the Kazakhstan Science Project № AP05134367«Synthesis of nanocrystals in track templates of SiO2/Si for sensory, nano-and optoelectronic applications» and Latvian Super Cluster (LASC), installed in the Institute of Solid State Physics (ISSP) of the University of Latvia. Authors are indebted to D. Gryaznov, A. Popov and A. Dauletbekova for stimulating discussions.Large scale ab-initio calculations are carried out to study the charge state transition levels of nitrogen and phosphorus impurity defects in zinc oxide crystals using the DFT-LCAO approximation as implemented into the CRYSTAL computer code. It is shown that at a high concentration of defects (close location of defects) their formation energy is underestimated due to a significant delocalization of the charge within the supercell. After inclusion the energy offset correction and defect-defective interaction, the formation energy is improved, in a comparison with that calculated in a large supercell. The optical transition levels obtained by a direct calculation confirm the experimental observation: nitrogen and phosphorus impurities are deep acceptor centers with large formation energy in a charged state and, therefore, cannot serve as the effective source of hole charge. The obtained results are in good agreement with the previous theoretical work, in which other calculation methods were used, and are capable of qualitatively describing the energy characteristics of the charged defects.University of Latvia; Institute of Solid State Physics, Chinese Academy of Sciences; Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART

Structure and Luminescence of YAG:Ce, Gd, Ga Ceramics Synthesized Radiation Assistedmethod

The work shows the possibility of radiation synthesis based on YAG:Ce ceramics. Synthesis was carried out by sintering samples from oxide powders in the field of high-energy electron flow. The lattice structure of synthesized samples of YAG:Ce and YAGG:Ce ceramics was compared with standards.The work was carried out within the framework of the grant AP08052050 of the Ministry of Education and Science of the Republic of Kazakhstan. This research was supported by Tomsk Polytechnic University CE Program

Structural and luminescent characteristics of YAG phosphors synthesized in the radiation field

YAG:Ce, YAGG:Ce ceramics were obtained by sintering the oxide powders in the radiation field. The results of investigations of the structure, composition and luminescence of ceramics are presented. The luminescence characteristics of powders exactly correspond to the phosphors luminescence used in practice obtained by solid-state synthesis methods. It has been established that in the used radiation exposure modes the main factor determining the efficiency of the synthesis is the ionization density

Structural and luminescent characteristics of YAG phosphors synthesized in the radiation field

YAG:Ce, YAGG:Ce ceramics were obtained by sintering the oxide powders in the radiation field. The results of investigations of the structure, composition and luminescence of ceramics are presented. The luminescence characteristics of powders exactly correspond to the phosphors luminescence used in practice obtained by solid-state synthesis methods. It has been established that in the used radiation exposure modes the main factor determining the efficiency of the synthesis is the ionization density