Heteroepitaxial growth of KCl and LiF on a cleaved (001) face of KBr

An initial stage of heteroepitaxial growth of KCl and LiF on a KBr substrate was studied using RHEED, EELS and AES. Both KCl and LiF films grow heteroepitaxially on a KBr substrate with their crystallographic axes parallel to that of substrate. In the case of KCl growth occurs in a well ordered layer-by-layer fashion and it is found that thickness of an intermediate region between KCl and KBr is less than 2 nm. In contrast three-dimensional island growth occurs in the case of LiF. Differences in lattice mismatch and solid solubility seem to determine the mechanism of heteroepitaxy of KCl and LiF on a KBr substrate.