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Observation by ESR of electrons localized at intrinsic shallow traps in silver halide systems
Author(s) -
Eachus R. S.,
Olm M. T.,
Janes R.,
Symons M. C. R.
Publication year - 1989
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.2221520220
Subject(s) - polaron , crystallite , electron , shallow donor , free electron model , chemistry , electron paramagnetic resonance , silver halide , cyclotron resonance , resonance (particle physics) , condensed matter physics , silver iodide , atomic physics , materials science , molecular physics , ion , nuclear magnetic resonance , crystallography , cyclotron , physics , quantum mechanics , organic chemistry , layer (electronics)
Abstract Electrons shallowly trapped at intrinsic sites in single‐crystal and polycrystalline samples of AgBr, AgCl, and mixed iodohalides are observed by ESR. The results are consistent with a model in which the electron is localised by a silver ion in an effective mass state. The observed ESR linewidths are explained in terms of exchange narrowing. The effect of iodide on the free or nearly‐free electron g ‐value is determined. Addition of iodide to AgCl or AgBr resulted in alloy line broadening. The amount of shallow trapping depended in part on dislocation density. In polycrystalline samples of AgBr, cyclotron resonance of the free electron polaron is observed simultaneously with the ESR signals from localized electrons. From the linewidth of the cyclotron resonance signal, the mobility of the free electron polaron in some polycrystalline samples is determined to be the same as that measured previously in very pure single crystals of AgBr.