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Photothermal Creation of Cu°v a + Centres and Mobility of Anion Vacancies in X‐Irradiated KCl:Cu Crystals
Author(s) -
Zazubovich S.,
Usarov A.,
Egemberdiev Zh.
Publication year - 1983
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.2221180235
Subject(s) - ion , vacancy defect , irradiation , crystallography , impurity , luminescence , dissociation (chemistry) , halide , atom (system on chip) , copper , chemistry , materials science , inorganic chemistry , physics , optoelectronics , organic chemistry , computer science , nuclear physics , embedded system
Associates of Cu° atoms with anion vacancies v a +(Cu°v a + centres) are used as luminescent detectors for the study of anion vacancy mobility in KCl crystals. It is found that near 220 K, Cu°v a +centres may be thermally formed because of the migration of v a +only to its neighbouring Cu° atom (i.e. the process occurs in {Cu°–v a − } pairs). An analogous process in {Cu + –v a + } pairs results in the creation of Cu + v a +centres. After Cu + v a +have trapped electrons released at the thermal destruction of Cu°, Cu°v a +centres are formed. {Cu + –v a + } and {Cu + –v a + } pairs are produced at low temperatures by the transfer of an F electron onto an impurity ion in irradiation‐generated {Cu + –F} and {Cu 2+ –F} pairs. If the crystal contains Cu a −centres, Cu°v a +centres may be formed at T > 370 K by the interaction of mobile V F centres, produced at a thermal dissociation of Cl 3 molecular ions, with Cu a −centres. It is proposed that at T < 300 K it is not the isolated but the “associated” anion vacancy that can migrate. This process occurs in the field of some defects and needs a comparatively lower activation energy than the motion of isolated v a + . The isolated or “free” v a +which are believed to be mobile at higher temperatures, are practically absent in X‐irradiated crystals at T > 250 K due to the interaction of v a +with mobile cation vacancies or interstitial halide ions as well as due to the thermal association of v a +with neighbouring lattice defects.