Thermoluminescence kinetic parameters of Bi4Ge3O12 single crystals (original) (raw)

Temperature dependence of Bi4Ge3O12 photoluminescence spectra

Materials Science-Poland, 2014

Bi 4 Ge 3 O 12 single crystals were obtained using Czochralski growth method. Photoluminescence spectra were analyzed versus temperature from 12 to 295 K. Besides the previously observed emission bands at 610 and 820 nm, the new emission band at 475 nm was found by a careful temperature dependence measurement in the present study. The influence of basic and defect structure on the shape and position of the spectra versus temperature was discussed.

Investigations of the non-isothermal crystallization of Bi4Ge3O12 (2:3) glasses

Journal of Non-Crystalline Solids, 2012

Amorphous Bi 4 Ge 3 O 12 glass samples were produced by melt quenching procedure stating with Bi 4 Ge 3 O 12 (BGO) powder, obtained by solid state reaction between oxides. The kinetics of non-isothermal crystallization of BGO nano-crystals has been investigated. Differential Thermal Analysis (DTA) can give the main parameters of crystallization with an exothermic peak from 813 K to 851 K depending on the heating rate, which was assigned to the crystallization of cubic BGO in the amorphous matrix and compared with the X-Ray Diffraction (XRD) patterns. The nano-crystal dimensions were calculated from the XRD patterns by using the Debye-Scherrer method and were compared with Transmission Electron Microscopy (TEM) images. It was shown that the Ozawa model is most suitable for describing the behavior of non-isothermal crystallization of BGO nano-crystals within the glass matrix. Experimental results suggest a disk-shape type growth mechanism for the Bi 4 Ge 3 O 12 nano-crystallites. The Flynn-Wall-Ozawa method has shown that the average activated energy value is 385 ± 14 kJ/mol which was computed within the same model and agrees very well with the activation energy of the crystallization.