On the saturation cluster density in deposition of thin films from vapours

A general formula is derived for the saturation cluster density ns of disc-shaped clusters in deposition of thin films from vapours. In the limiting cases of complete and incomplete condensation, explicit expressions are obtained for the dependence of ns on the deposition rate and the substrate temperature. The results apply to immobile clusters nucleated at atomically high supersaturations on a substrate without active sites. Some of the theoretical findings are compared with existing experimental data for gold and silver deposited onto alkali halide substrates.