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Title: Electron spin resonance study of self-trapped holes in CdWO{sub 4} scintillator crystals

Abstract

The self-trapping of holes at oxygen anions was studied by electron spin resonance in UV irradiated CdWO{sub 4} crystals. Analysis of superhyperfine interaction of the holes with {sup 183}W and {sup 111,113}Cd isotopes shows that the self-trapped hole is either delocalized in the space between two energetically equivalent nearest neighbor oxygen ions or tunnels between them. When the temperature increases above 40-50 K the self-trapped holes are thermally liberated and can be retrapped by oxygen ions perturbed by impurity ions. In case of the Nb{sup 5+} or Li{sup +} stabilizing impurities the O{sup -} centers are thermally stable up to 160-170 K. The study of kinetic characteristics of the self-trapped holes suggests that holes leave oxygen ions by thermally assisted tunneling mechanism via two slightly different channels. Corresponding ionization probabilities are defined by the Arrhenius law with an average thermal ionization energy E=90(5) meV. Calculated pre-exponential factors, about 10{sup 5} s{sup -1}, are small, which is consistent with the tunneling mechanism. Thermal stability and kinetic characteristics of the trapped holes are discussed in light of the scintillation and thermoluminescence characteristics of CdWO{sub 4}.

Authors:
 [1]; ;  [1]; ; ;  [2]
  1. Institute of Physics, AS CR, Cukrovarnicka 10, 162 53 Prague (Czech Republic)
  2. Institute for Scintillation Materials, NASc of Ukraine, 60 Lenin Ave., 61001 Kharkov (Ukraine)
Publication Date:
OSTI Identifier:
21185922
Resource Type:
Journal Article
Journal Name:
Journal of Applied Physics
Additional Journal Information:
Journal Volume: 104; Journal Issue: 10; Other Information: DOI: 10.1063/1.3028228; (c) 2008 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0021-8979
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ANIONS; CADMIUM 111; CADMIUM 113; CADMIUM TUNGSTATES; CRYSTALS; ELECTRON SPIN RESONANCE; HOLES; IONIZATION; ISOTOPE EFFECTS; LITHIUM IONS; NIOBIUM IONS; OXYGEN IONS; PARAMAGNETISM; TEMPERATURE DEPENDENCE; TEMPERATURE RANGE 0013-0065 K; TEMPERATURE RANGE 0065-0273 K; THERMOLUMINESCENCE; TRAPPING; TUNGSTEN 183; TUNNEL EFFECT

Citation Formats

Laguta, V V, Institute for Problems of Material Science, NASc of Ukraine, Krjijanovskogo 3, 03680 Kiev, Nikl, M, Rosa, J, Grinyov, B V, Nagornaya, L L, and Tupitsina, I A. Electron spin resonance study of self-trapped holes in CdWO{sub 4} scintillator crystals. United States: N. p., 2008. Web. doi:10.1063/1.3028228.
Laguta, V V, Institute for Problems of Material Science, NASc of Ukraine, Krjijanovskogo 3, 03680 Kiev, Nikl, M, Rosa, J, Grinyov, B V, Nagornaya, L L, & Tupitsina, I A. Electron spin resonance study of self-trapped holes in CdWO{sub 4} scintillator crystals. United States. https://doi.org/10.1063/1.3028228
Laguta, V V, Institute for Problems of Material Science, NASc of Ukraine, Krjijanovskogo 3, 03680 Kiev, Nikl, M, Rosa, J, Grinyov, B V, Nagornaya, L L, and Tupitsina, I A. 2008. "Electron spin resonance study of self-trapped holes in CdWO{sub 4} scintillator crystals". United States. https://doi.org/10.1063/1.3028228.
@article{osti_21185922,
title = {Electron spin resonance study of self-trapped holes in CdWO{sub 4} scintillator crystals},
author = {Laguta, V V and Institute for Problems of Material Science, NASc of Ukraine, Krjijanovskogo 3, 03680 Kiev and Nikl, M and Rosa, J and Grinyov, B V and Nagornaya, L L and Tupitsina, I A},
abstractNote = {The self-trapping of holes at oxygen anions was studied by electron spin resonance in UV irradiated CdWO{sub 4} crystals. Analysis of superhyperfine interaction of the holes with {sup 183}W and {sup 111,113}Cd isotopes shows that the self-trapped hole is either delocalized in the space between two energetically equivalent nearest neighbor oxygen ions or tunnels between them. When the temperature increases above 40-50 K the self-trapped holes are thermally liberated and can be retrapped by oxygen ions perturbed by impurity ions. In case of the Nb{sup 5+} or Li{sup +} stabilizing impurities the O{sup -} centers are thermally stable up to 160-170 K. The study of kinetic characteristics of the self-trapped holes suggests that holes leave oxygen ions by thermally assisted tunneling mechanism via two slightly different channels. Corresponding ionization probabilities are defined by the Arrhenius law with an average thermal ionization energy E=90(5) meV. Calculated pre-exponential factors, about 10{sup 5} s{sup -1}, are small, which is consistent with the tunneling mechanism. Thermal stability and kinetic characteristics of the trapped holes are discussed in light of the scintillation and thermoluminescence characteristics of CdWO{sub 4}.},
doi = {10.1063/1.3028228},
url = {https://www.osti.gov/biblio/21185922}, journal = {Journal of Applied Physics},
issn = {0021-8979},
number = 10,
volume = 104,
place = {United States},
year = {Sat Nov 15 00:00:00 EST 2008},
month = {Sat Nov 15 00:00:00 EST 2008}
}