Cuprous Halide Films on Alkali Halide Crystals

Abstract

Films of cuprous halides were formed by evaporation and condensation in a vacuum onto substrates of alkali halide crystals at room temperature. They were annealed for 15 min periods at temperatures between 60° and 150°C. Optical absorption spectra indicate that the annealing causes diffusion of CuCl and CuBr into KCl and KBr, but not into KI or NaCl, and of CuI into RbI, but not into KCl, KBr, KI, or NaCl. An interstitial mechanism for diffusion is consistent with the data but is not sufficient to account for the behavior of CuI.