PHOTOLUMINESCENCE OF LANTHANUM CHALCOGENIDE GLASSES

The photoluminescence, excitation, and edge transmission spectra of la nthanum chalcogenide glasses are studied. Substitution of selenium or tellurium for sulfur in La2S3 . 2Ga(2)O(3) glass leads to a redshift o f the edge transmission and luminescence excitation spectra because of the decrease in band gap. The narrowing of the band gap and the incre ase in interatomic distances and dielectric permittivity alter the pos ition of [(V-La)(2)(0)-D-0](0) radiative-recombination centers, shifti ng the red emission (0.68-0.73 mu m in the parent glass) to the IR reg ion (0.8-0.85 mu m). The position of the levels related to unassociate d lanthanum vacancies remains unchanged.