Molecular orientation and ordering in CoPc and FePc thin films grown on Au(001)-5×20

Abstract

Molecular orientation and ordering in thin films of the organic semiconductors cobalt- and iron-phthalocyanine (CoPc and FePc) grown in situ on a Au(001)-5×20 surface have been studied by a combination of low energy electron diffraction (LEED) and near-edge x-ray absorption fine structure (NEXAFS) spectroscopy. The results indicate that the molecular planes of CoPc and FePc deposited at a substrate temperature of about 250 °C lie parallel to the Au(001)-5×20 surface. The LEED patterns and NEXAFS data demonstrate that the overlayers are highly ordered with a square unit cell of approximately 14.2×14.2 Å2 aligned along the ⟨110⟩ and ⟨1 1¯0⟩ axes of the Au(001) surface.