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Temperature Dependence of Defect Production in KBr and KCl (II)
Author(s) -
Comins J. D.
Publication year - 1971
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.2220430111
Subject(s) - irradiation , decomposition , atmospheric temperature range , growth rate , chemistry , production (economics) , range (aeronautics) , materials science , analytical chemistry (journal) , thermodynamics , physics , nuclear physics , composite material , mathematics , organic chemistry , chromatography , geometry , macroeconomics , economics
Studies of the growth of F‐centres in Harshaw KBr and KCl during X‐irradiation as a function of temperature show that the “late‐stage” production rate progressively decreases as the temperature of irradiation T is increased above ≈ 195 °K for KBr and above ≈ 213 °K for KCl. Various mechanisms are examined to explain this effect. The results are found to be in semi‐quantitative agreement with the predictions of the excitonic mechanism of defect production, but arguments are presented to show that the mechanism of suppression involving mobile vacancies makes some contribution. The V‐bands formed in the range investigated (195 °K < T < 298 °K) show a continuing progressive change in shape and peak position with increasing temperature of irradiation. Their growth behaviour becomes increasingly non‐proportional to F‐centre growth as T increases, but nevertheless the overall “late‐stage” rate decreases in a manner comparable with that found for F‐centres, and provides evidence that they are of an interstitial nature. The growth of the 213 nm band shows a two‐stage behaviour, the first resulting from decomposition of OH − centres to form the U‐band, while the later stage is considered to be due to the formation of V 3 ‐centres.