Larisa Grigorjeva, Aleksejs Zolotarjovs, Sergej Yu Sokovnin, Donats Millers, Krisjanis Smits, Vladislav G. Il`ves
Two types of ZnO ceramics were fabricated and characterized by XRD, SEM methods. The radioluminescence spectra were measured within the 300–550 K range. The defect luminescence band peaking at ~2.35 eV is the dominant one in radioluminescence spectra in both of the fabricated ceramics. The thermostimulated luminescence (TSL) glow-curves were measured after X-ray irradiation at 300 K. It was concluded that the complex overlapping peak within the 320–450 K temperature range consists of two components (~360–375 K and 400–420 K). The ratio of component intensities differs in both ceramics. The positions of high temperature TSL components (480–520 K) also differ in both samples; therefore not only sintering conditions but also the properties of the initial powder are very important for characteristics of TSL. A linear dependence of peak intensity on irradiation dose was observed up to ~3 kGy for ceramic 1 and up to 9 kGy for ceramic 2.
L. Grigorjeva , D. Millers , K. Smits , A. Sarakovskis , W. Lojkowski , A. Swiderska-Sroda , W. Strek ,
Transparent Ce and Ce/Pr doped YAG ceramics were prepared under high pressures (up to 8 GPa) and relative
low temperature (450 C). Grain size of the ceramics is less than 50 nm. However unknown defects
or disorders strains on grain boundaries caused the additional absorption in these ceramics. The luminescence
intensity, spectra and the decay time dependence on pressure applied during ceramic preparation
were studied. Concentration of some intrinsic point defect was reduced under the high pressure applied
for sintering process.
It is shown that formation time of the excited state of Ce luminescence depends on the pressure applied
during ceramic sintering.
Optical Materials 34 (2012) 986–989
L. Grigorjeva , D. Millers , K. Smits , V. Pankratov , W. Łojkowski, J. Fidelus , T. Chudoba , K. Bienkowski , C. Monty
Fast photoluminescence spectra in the spectral region of 3.1–3.45 eV in ZnO and ZnO:Al ceramics were
studied at 14 and 300 K. Ceramics with grains smaller than 100 nm were sintered from nanopowders
by high pressure (8 GPa) and low temperature (350 C). Ceramics with grain sizes 1–5 lm were sintered
at 1400 C. It is shown that excitonic luminescence spectra depend on the ceramics grain size, post preparing
annealing and doping. The excitonic luminescence decay time was faster than 2 ns and the afterglow
at 30 ns was 0.05%.
Optical Materials 2009
Larisa Grigorjeva, Donats Millers, Janis Grabis, Claude Monty, Aleksandr Kalinko, Krishjanis Smits,
Vladimir Pankratov, and Witold Łojkowski
Abstract—The luminescence excitation spectra, luminescence
spectra and the nanosecond-scale decay kinetics were studied.
The ZnO and ZnO:Al nanopowders were prepared by vaporization-
condensation in a solar furnace using different raw powders:
commercial, hydrothermal and those obtained by plasma synthesis.
Exciton-phonon as well as exciton-exciton interaction
processes in nanopowders, a bulk crystal and ZnO ceramics were
studied and compared. The fast decay and low afterglow intensity
of ZnO nanopowders and ceramics support these materials for
IEEE Transactions on Nuclear Science, VOL. 55, NO. 3, JUNE 2008
Digital Object Identifier 10.1109/TNS.2008.921931