Epitaxial growth of a methoxy-functionalized quaterphenylene on alkali halide surfaces

• Growth of a methoxy-functionalized para-phenylene on dielectric surfaces is investigated.
• Low-energy electron diffraction and X-ray diffraction techniques are employed for structural characterization.
• Epitaxial growth of upright molecules only is documented.
• Polarized optical microscopy together with atomic force microscopy complements the findings.

The epitaxial growth of the methoxy functionalized para-quaterphenylene (MOP4) on the (001) faces of the alkali halides NaCl and KCl and on glass is investigated by a combination of low energy electron diffraction (LEED), polarized light microscopy (PLM), atomic force microscopy (AFM), and X-ray diffraction (XRD). Both domains from upright molecules as well as fiber-like crystallites from lying molecules form. Neither a wetting layer from lying molecules nor widespread epitaxial fiber growth on the substrates is detected. Our results focus on the upright standing molecules, which condense into a thin film phase with an enlarged layer spacing compared to the bulk phase.