Epitaxial C60 films on CaF2 (111) grown by molecular beam deposition

Epitaxial C60 films grown by molecular beam deposition onto CaF2(111) surfaces are investigated by reflection high‐energy electron diffraction at deposition temperatures of 30–300 °C and coverages corresponding to average thicknesses of 1–50 nm. Over this entire temperature range, C60 forms an incommensurate overgrowth of stacked hexagonal layers exhibiting a characteristic nearest‐neighbor spacing of 0.98 nm. Below 170 °C, unidirectional growth occurs in accordance with the crystallographic directions of the substrate. At higher deposition temperatures, however, two equivalent, rotated domain orientations are observed which are characterized by a significantly lower degree of lattice mismatch.