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Energy‐filtering TEM and electron energy‐loss spectroscopy of double structure tabular microcrystals of silver halide emulsions
Author(s) -
JACOB W.
Publication year - 1996
Publication title -
journal of microscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.569
H-Index - 111
eISSN - 1365-2818
pISSN - 0022-2720
DOI - 10.1046/j.1365-2818.1996.73068.x
Subject(s) - electron energy loss spectroscopy , silver halide , spectroscopy , materials science , k edge , crystal (programming language) , transmission electron microscopy , molecular physics , crystallography , analytical chemistry (journal) , chemistry , optics , absorption spectroscopy , physics , nanotechnology , layer (electronics) , computer science , programming language , quantum mechanics , chromatography
Composite Ag(Br,I) tabular microcrystals of photographic emulsions were studied by the combination of energy‐filtering electron microscopy (EFTEM) and electron energy‐loss spectroscopy (EELS) in conjunction with energy‐dispersive X‐ray (EDX) microanalysis. The contrast tuning under the energy‐filtering in the low‐loss region was used to observe more clearly edge and random dislocations, {11 − 1} stacking faults in the grain shells parallel to {11 − 2} edges and bend and edge contours. Electron spectroscopic diffraction patterns revealed numerous extra reflections at commensurate positions in between the Bragg reflections and diffuse honeycomb contours; these were assigned to the number of defects in the shell region parallel to the grain edges and polyhedral clusters of interstitial silver cations, respectively. Inner‐shell excitation bands of silver halide were detected and confirmed by EDX analyses, i.e. the Ag N 2,3 edge at 62 eV (probably overlapped with the weak I N 4,5 edge at 52 eV and the Br M 4,5 edge at 70 eV), the I M 4,5 edge at about 620 eV, and the Br L 2,3 edge at about 1550 eV energy losses. Energy‐loss near‐edge structure of the Ag M 4,5 edge at about 367 eV energy losses and low‐loss fine structure arisen as a result of interband transitions and excitons, possibly superimposed with many electron effects, have been revealed. The crystal thickness was determined by a modified EELS log‐ratio technique in satisfactory agreement with measurements on grain replicas.