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Crystals of BSO doped with Se in two different concentrations (BSO:Se(I) and BSO:Se(II)) were grown by the Czochralski method. It is established that doping with Se is accompanied with preferential absorption of Fe from the melt. According to the in-depth chemical analysis, it is assumed that the doping Se ions enter the tetrahedral positions by means of the substitution of 3Si4+ by (Se6+ + 2Fe3+) ions. The measured absorption spectrum of the low-concentration Se-doped crystal (BSO:Se(I)) confirms such a conclusion as the absorption coefficient is increased in a broad spectral interval (1.4–3.1 eV) – an effect typical for all Fe-doped Bi12SiO20 crystals. The polarized Raman spectra of BSO:SeI show that the doping-induced lattice distortions are small. The IR spectrum of the BSO:SeI crystal yields indications for local lowering of the symmetry of the Fe-occupied tetrahedral positions. Doping with Se at high concentration (BSO:Se(II)) leads to occasional second phase inclusions and to a downshift of practically all modes in the Raman spectrum by 2–5.5 cm−1. It is concluded that the doping with Se at high concentrations follows the same mechanism as that at low concentrations but the introduced lattice distortions are more significant, and lead to an enlargement of the unit cell while preserving the overall cubic symmetry.

Optical quality single crystals and epitaxial films of Bi24B2O39 compound crystallized in sillenite-type structure have been fabricated by TSSG and liquid-phase epitaxy methods, respectively. A deviation of power rotation vs. wavelengths in visible is recorded. The important characteristics, such as: absorption, circular dichroism, photoinduced absorption, photoconductivity and dark conductivity are studied. Comparison of these characteristics is done for diAerent sillenites. ” 1999 Elsevier Science B.V. All rights reserved.

The bulk bismuth aluminate Bi2Al4O9 and gallate Bi2Ga4O9 scintillative crystals have been grown from a high temperature self-flux solution adopting a top seeded technique. The lattice parameters and density of the compounds have been appropriately determined based on single crystals and powder pattern technique as well. The reflectivity, absorption and photoluminescence spectra of as grown crystals are reported. Green-yellow and red emission bands for both compounds have been readily recorded at 300 K, while the red luminescence can be sufficiently effective excited by high energy electron beam. The difference of excitation band position for crystals studied is evidently presented. Two decay time components equal 25 and 155 ns for Bi2Al4O9 crystal have been detected at room temperature.