0000000000594764
AUTHOR
Dzintars Berzins
Recombination luminescence of X-ray induced paramagnetic defects in BaY2F8
This research is funded by the Latvian Council of Science , project “Novel transparent nanocomposite oxyfluoride materials for optical applications”, project No. LZP-2018/1–0335 . The crystal growth research was funded by the CNPq (Brazil), project NO 421581/2016–6 .
Luminescence of phosphorus containing oxide materials: Crystalline SiO2‐P and 3P2O5⋅7SiO2; CaO⋅P2O5; SrO⋅P2O5 glasses
Luminescence of phosphate glasses such as CaO⋅P2O5 and SrO⋅P2O5 is compared with that of phosphorus doped crystalline α-quartz and phosphosilicate glass with content 3P2O5⋅7SiO2. Water & OH groups are found by IR spectra in these materials. The spectrum of luminescence contains many bands in the range 1.5 - 5.5 eV. The luminescence bands in UV range at 4.5-5 eV are similar in those materials. Decay duration in exponential approximation manifests a time constant about 37 ns. Also a component in μs range was detected. PL band of μs component is shifted to low energy with respect to that of ∼37 ns component. This shift is about 0.6 eV. It is explained as singlet-triplet splitting of excited st…
Spectroscopic study of the electric field induced valence change of Fe-defect centers in SrTiO(3)
The electrochemical changes induced by an electric field in Fe-doped SrTiO(3) have been investigated by X-ray absorption spectroscopy (XANES and EXAFS), electron paramagnetic resonance (EPR) and Raman spectroscopy. A detailed study of the Fe dopant in the regions around the anode and cathode reveals new insights into the local structure and valence state of Fe in SrTiO(3) single crystals. The ab initio full multiple-scattering XANES calculations give an evidence of the oxygen vacancy presence in the first coordination shell of iron. Differences in the length and disorder of the Fe-O bonds as extracted from EXAFS are correlated to the unequivocal identification of the defect type by compleme…
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 1.5–5.5 eV. The luminescence bands in UV range at 4.5–5 eV are similar in those materials. Decay duration in exponential approximation manifests a time constant about 37 ns. Also a component in µs range was detected. PL band of µs component is shifted to low energy with respect to that of ~37 ns component. This shift is about 0.6 eV. It is explained as singlet–triplet splitting of excited state. Below 14 K increase of luminescence kinetics du…