TRANSMISSION ELECTRON-MICROSCOPY STUDIES OF (111)TWINNED SILVER-HALIDE MICROCRYSTALS

The present paper covers the results of different transmission electro n microscopy studies on silver halide microcrystals. Pure AgBr as well as core-shell AgBr-AgBrI crystals are investigated. In the former par allel and non-parallel twinning modes yielding tabular and needle- or tetrahedral-shaped microcrystals, respectively, are discussed. Also th e short-range-order of Ag+ interstitials around the twin planes as det ermined from diffuse intensity in reciprocal space is described. The l atter yields a technique to determine the variant in which dislocation s are located in certain core-shell microcrystals. The introduction of iodine also results in the presence of inclined stacking faults in th e shell and of long-range iodine ordering on the crystal surface. (C) 1998 Wiley-Liss, Inc.