The role of contaminants in the epitaxial growth of gold on sodium chloride

Abstract

Abstract It has recently been found that the growth of gold foils, in the orientation of their sodium chloride substrates, is aided by exposing the salt surface to air prior to the deposition of gold upon it. This is not because an exposure to air improves the alignment of the initial gold nuclei. The epitaxial alignment of thin (1 Å) gold deposits on clean sodium chloride is actually more perfect than it is in thin deposits grown on salt that had previously been exposed to air. The important effect of exposing a salt surface to air is to increase the number of gold nuclei that are formed upon it. This increase causes the gold nuclei to coalesce early in film growth. The stage in film growth at which coalescence occurs has been found to have a strong influence on the orientation changes that accompany coalescence, and thus on the orientation of the complete gold film.