Electron paramagnetic resonance study of hole trapping at defects in silver halides

This is the authors' abstract. We don't add key points for this paper.

Hole-trapping at cation vacancies and iodide impurity in silver halides was studied by means of electron paramagnetic resonance (EPR). In AgCl, the hole was found to be preferentially self-trapped on a Ag ion next to a cation vacancy, forming a perturbed self-trapped hole center. The position of the vacancy relative to the center of the STH was determined, by comparison of computer simulations to the experimental EPR spectra, to be in either the nearest-neighbor or next-nearest-neighbor equatorial position. The thermal trap depths of the hole in these centers are estimated to be 0.31 and 0.24 eV, respectively. For lightly doped (several tens of ppm) AgBr:I, an interesting spectrum has been observed, consisting of six equidistant and approximately equi-intense hyperfine EPR lines, consistent with a trapped hole localized at an iodide ion (nuclear spin 5/2), but not with an iodide-perturbed STH.