Luminescence quenching by iron in barium aluminoborate glasses

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The quenching of the radiative e--h+ recombination in barium aluminoborate glass, x irradiated at 77 K, was investigated by EPR and thermoluminescence (TL) techniques as a function of an iron impurity concentration ranging from 10(-3) to 0.1 at. %. The analysis of the EPR line shape of Fe3+, observed in these glasses, suggested that a large fraction of Fe impurity occupies substitutional sites of the glass-forming network, locally charge compensated by a pair of Ba2+ interstitial cations. The electron untrapping activation energy from the boron electron centers [D. L. Griscom, J. Chem. Phys. 55, 1113 (1971)], obtained from the TL initial slope, is equal to 0.21 eV. The correlation between the TL intensity and the Fe concentration was found to be exponential, and is discussed on the basis of some recent theories for the nonradiative e--h+ recombination mechanism.