Orientation study of iron Phthalocyanine (FePc) thin films deposited on silicon and gold surfaces

In this paper, we present the effect of annealing on the orientation of iron Phthalocyanine (FePc) thin films deposited on cleaned silicon and gold coated silicon substrates. The thin films were obtained by thermal evaporation technique and were exposed to air for physical characterisation. Room temperature x-ray diffraction (XRD), hard x-ray photoelectron spectroscopy (HAXPES) and polarized soft x-ray absorption spectroscopy (XAS) were carried out to study the orientation of these thin films. The obtained results showed that the un-annealed FePc thin films on gold coated Si substrate were amorphous in nature. However, annealed FePc thin films on Si substrate and gold coated Si substrate were crystalline in nature. Annealed FePc thin films on Si substrate got ordered in the edge-on stacking (with FePc molecular plane normal to Si surface) mode and annealed FePc thin films on gold coated Si substrate got ordered in the face-on stacking (with FePc molecular plane parallel to the gold surface) mode.