UV and yellow luminescence in phosphorus doped crystalline and glassy silicon dioxide

Abstract

Luminescence of phosphorus doped crystalline α-quartz and phosphosilicate glass with content 3P2O5·7SiO2 was studied. Water and OH groups are found by IR spectra in these materials. The spectrum of luminescence contains many bands in the range 1.5–5.5eV. The luminescence bands in UV range at 4.5–5eV are similar in those materials. Decay duration in exponential approximation manifests a time constant about 37ns. Also a component in µs range was detected. PL band of µs component is shifted to low energy with respect to that of ~37ns component. This shift is about 0.6eV. It is explained as singlet–triplet splitting of excited state. Below 14K increase of luminescence kinetics duration in µs range was observed and it was ascribed to zero magnetic field splitting of triplet excited state of the center.Yellow–red luminescence was induced by irradiation in phosphorus doped crystalline α-quartz, phosphosilicate glasses. The yellow luminescence contains two bands at 600 and 740nm. Their decay is similar under 193nm laser and may be fitted with the first order fractal kinetics or stretched exponent. Thermally stimulated luminescence contains only band at 600nm. The 248nm laser excites luminescence at 740nm according to intra center process with decay time constant about 4ms at 9K.Both type of luminescence UV and yellow were ascribed to different defects containing phosphorus.P-doped α-quartz sample heated at 550°C become opalescent. IR spectra related to water and OH groups are changed. Photoluminescence intensity of all three bands, UV (250nm), yellow (600nm) and red (740nm) strongly diminished and disappeared after heating to 660°C. Radiation induced red luminescence of non-bridging oxygen luminescence center (NBO) appeared in crystal after heat treatment. We had observed a crystalline version of this center (Skuja et al., Nuclear Instruments and Methods in Physics Research Section B Beam Interactions with Materials and Atoms. 2012; 286: pp. 159–168). Effect of heat treatment explained as sedimentation of phosphorus in some state. Keeping of treated sample at 450–500°C leads to partial revival of ability to create yellow luminescence center under irradiation.