| 1. |
- Kotlov, A, et al.
(author)
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Luminescence study of self-trapped holes in pure and Fe- or Mo-doped ZnWO4 crystals
- 2004
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In: LUMDETR2003. - : Elsevier BV. ; 38, s. 715-715
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Conference paper (peer-reviewed)abstract
- Thermostimulated and photostimulated luminescence of ZnWO4, ZnWO4:Fe and ZnWO4:MO Crystals irradiated at low temperatures by X-rays or UV photons was studied in the temperature range 4.2-300 K in order to clarify the creation and recombination processes of the elementary colour centres. The connection of the luminescence phenomena with the self-trapped holes has been revealed. (C) 2003 Published by Elsevier Ltd.
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| 2. |
- Nagirnyi, V, et al.
(author)
-
Luminescence study of pure and Fe- or Mo-doped ZnWO4 crystals
- 2004
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In: Radiation Measurements. - : Elsevier BV. - 1879-0925 .- 1350-4487. ; 38:4-6, s. 519-522
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Journal article (peer-reviewed)abstract
- ZnWO4, ZnWO4 : Fe and ZnWO4 : Mo crystals were investigated by the methods of time-resolved spectroscopy in the temperature range of 4.2-300 K. It is shown that the Mo and Fe impurities significantly reduce the light yield of ZnWO4. The main 2.5 eV emission of ZnWO4 and the 1.77 eV emission band of ZnWO4 : Mo are shown to originate from the triplet excited state of the WO6 and MoO6 complex, respectively. In ZnWO4 : Fe,Mo the MoO6 emission band is shifted to lower energies due to the perturbing influence of the iron impurity. No perturbing effect of Fe or Mo ions was observed for the main emission of ZnWO4 : Fe and ZnWO4 : Mo. The creation spectrum of self-trapped holes was measured for ZnWO4, ZnWO4 : Fe and ZnWO4 : Mo crystals in the energy region of 4-30 eV. (C) 2004 Elsevier Ltd. All rights reserved.
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| 3. |
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| 4. |
- Nagirnyi, V, et al.
(author)
-
Energy transfer in ZnWO4 and CdWO4 scintillators
- 2002
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In: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - 0167-5087. ; 486:1-2, s. 395-398
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Journal article (peer-reviewed)abstract
- A systematic spectroscopic study of oriented single ZnWO4 crystals was performed using UV and synchrotron excitation. Emission and phosphorescence spectra in the energy region 1-4 eV as well as reflection spectra and excitation spectra of various emissions and phosphorescence in the energy region 3.5-32eV were studied at 4.2-300K using synchrotron radiation. The results are compared to those available for CdWO4. The peculiarities of the band structure and those of excitonic and electron-hole processes in the systems investigated are discussed.
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| 5. |
- Nagirnyi, V, et al.
(author)
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Iron-related luminescence centers in ZnWO4 : Fe
- 2002
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In: Radiation Effects and Defects in Solids. - : Informa UK Limited. - 1042-0150 .- 1029-4953. ; 157, s. 1123-1123
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Journal article (peer-reviewed)abstract
- A systematic spectroscopic study of single ZnWO4 :Fe crystals with different iron concentrations has been performed under excitation by ultraviolet light, by synchrotron radiation or under photostimulation by near-infrared light. The luminescence of Fe3+-related centres has been studied. It is shown that iron centres of different types efficiently promote the formation of crystal defects at low temperatures. Electrons and holes can be trapped near Fe2+ or Fe3+ ions, which is further revealed in phosphorescence, thermostimulated or photostimulated luminescence. At room temperature the main effect of iron impurity is to reduce the light yield of a ZnWO4 scintillator.
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| 6. |
- Nagirnyi, V, et al.
(author)
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Separation of excitonic and electron-hole processes in metal tungstates
- 2003
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In: Journal of Luminescence. - 0022-2313. ; 102, s. 597-603
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Journal article (peer-reviewed)abstract
- Absorption, reflection and emission polarization spectra of CdWO4 crystals have been studied in the region 3.5-30 eV in order to distinguish the excitonic and electron-hole processes in the vicinity of the band gap. The following parameters have been defined from the Urbach tail study at 6-300 K: E-0 = 5 eV, sigma(0) = 0.31, homega = 70 meV (565 cm(-1)). Excitonic processes have been shown to dominate at excitation of tungstate crystals in the lower part of the conduction band. Excitons are formed due to the transitions into the tungstate W5d states hybridized with O6p and possess a very strong tendency for self-trapping. Free electrons and holes can be created at the energies 1-2 eV (depending on the crystal) higher than the bottom of the conduction band due to the transitions into cationic states. (C) 2003 Elsevier Science B.V. All rights reserved.
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| 7. |
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