We have performed a series of experiments in which the heteroepitaxial grow
th of rubidium iodide on mica was carried out by precipitation from aqueous
solution. The process was studied using time-lapse optical microscopy, ex
situ atomic-force microscopy, and x-ray diffraction. We find that this is a
n extremely robust epitaxial growth system, in that highly oriented islands
are formed over a wide range of temperatures and evaporation rates. From t
he x-ray measurements we find that die distribution of azimuthal island ori
entations is in most cases less than 0.3 degrees wide, despite the fact tha
t growth rates are generally well over 1 mu m/s. Using EX situ atomic-force
microscopy, we show that during early stages of growth the external morpho
logy of the epitaxial islands crosses over from a circular island shape to
a triangular one, at an island size of approximately 1 mu m. Overall, the g
rowth of salts on mica provides a rich environment in which to probe nuclea
tion and growth phenomena as functions of temperature, evaporation rate, an
d epitaxial misfit. [S0163-1829(98)02345-5].