Absence of template induced ordering in organic multilayers: The growth of pentacene on a Cu(221) vicinal surface

The structure and morphology of pentacene films grown on a Cu(221) vicinal surface have been studied by means of scanning tunneling microscopy (STM), low energy electron diffraction (LEED) and atomic force microscopy (AFM). Well ordered saturated monolayer films were prepared by first depositing few nanometers pentacene at room temperature followed by brief heating above 400 K in order to sublimate the multilayer excess. The chemisorbed monolayer adopts a (1 × 7) superstructure with a uniform alignment of the molecules along the step edges while upon further deposition this template induced ordering is not transferred to multilayer films. Instead the molecules continue to grow in an upright orientation and form pyramidal islands without any substrate related azimuthal orientation.