Structural properties of epitaxially grown perfluoron-alkanethin films prepared by vapor deposition

Structural and orientational studies of epitaxially grown perfluoron-alkane(CF3(CF2)18CF3) thin films evaporated on KCl(001) substrates were conducted by an energy dispersive total reflection X-ray diffractometer. Then-C20F42molecules grow epitaxially on the KCl(001) surface owing to the slight interaction between the terminal CF3 groups and KCl(001), arranging their 〈100〉hex directions along the KCl 〈110〉 directions. The detailed analysis suggests that most of the molecules crystallize on the epitaxially grown underlayers with the same orientational distribution, although the population of the crystallite with randomly oriented domain structure is slightly increased with increasing thickness. Furthermore, the distorted epitaxial growth with an inclination about ±5° from the KCl 〈110〉 directions was observed and its origin was discussed with respect to the lattice relationship.