Annual Report 2012 - Latvijas Universitātes Cietvielu fizikas institūts

charge carrier migration before trapping at centers responsible for the absorption. The
formation rate of absorption centers and decay rate of absorption depend on the photon
energy. The kinetics of short lived absorption varies over spectrum and can be
approximated with a stretched exponent. The stretched exponent parameters indicate that
the local disorder of a matrix is similar around all absorption centers.
NEAR-BAND LUMINESCENCE OF CdZnTe DETECTOR CRYSTALS
L.Grigorjeva, D.Millers, V.Ivanov, L.Aleksejeva
For the for nondestructive detector material selection the low temperature near-band
luminescence measurements will be carried out and analyzed. It is shown that the
complex of parameters such as presence and intensity of A and DAP luminescence
bands, the decay kinetics in A 0 Ex-1LO and DAP luminescence bands, the peak position
and FWHM of D 0 Ex luminescence are more important characteristics. The A 0 Ex-1LO
and DAP luminescence peaks overlaps and conclusion about the DAP luminescence will
be done from luminescence decay measurements. The DAP luminescence has nonexponential
decay. Usually, acceptors – V cd ; donors – Te Cd . The A 0 Ex-1LO
luminescence is fast with decay time 2-3 ns.
Zirconia nanocrystals as submicron level biological label
K.Smits, J.Liepins, M.Gavare, A.Patmalnieks, A.Gruduls, Dz.Janlovica
Inorganic nanocrystals are of increasing interest for their usage in biology and
pharmatalogy research. We study the usage of ZrO 2 nanocrystals as submicron level
biological label in baker’s yest Saccharomyces cerevisia culture. The images with sub
micro up-conversion luminescence particles in biologic media were made. A set of
undoped as well as Er and Yb doped ZrO 2 nanopowders with different dopand
concentration were prepared by sol-gel method. The up-conversion luminescence for
free standing and for nanocrystals with baker’s yeast cells was studied and the
differences in up-conversion luminescence spectra were analyzed. In vivo toxic effects
of ZrO 2 nanocrystals were tested by co-cultivation with baker’s yest.
Scientific publications
1. Dorogov P., Ivanov V., Loutchanski A., Grigorjeva L., Millers D. Improving the
performance of μ CdZnTe detectors using infrared stimulation. 2012, IEEE Transactions
on Nuclear Science 59 (5 PART 3) , art. no. 6327737 , pp. 2375-2382.
2. Zabels, R., Muktepavela F., Grigorjeva L.Deformation behavior of nanostructured
ZnO films on glass.. 2012, Thin Solid Films 520 (14) , pp. 4685-4688.
3. Grigorjeva, L., Millers, D., Smits, K., Sarakovskis, A., Lojkowski, W., Swiderska-
Sroda A., Strek W., Gluchowski P.The time-resolved luminescence characteristics of Ce
and Ce/Pr doped YAG ceramics obtained by high pressure technique. 2012, Optical
Materials 34 (6) , pp. 986-989.
4. Dorogov, P., Ivanov, V., Loutchanski, A., Grigorjeva, L., Millers, D. Improving the
performance of CdZnTe detectors using infrared stimulation. IEEE Nuclear Science
Symposium Conference Record , 2012 art. no. 6154734 , pp. 4557-4561.
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