Epitaxial Growth of Iron Phthalocyanine at the Initial Stage on Au(111) Surface

Growth behavior of iron(II) phthalocyanine (FePc) molecules on Au(111) surface at the initial stage is studied with low-temperature scanning tunneling microscopy. The FePc molecules are separately adsorbed on the face-centered cubic and the hexagonal close-packed regions at the submonolayer regime, indicating that the molecular adsorption is greatly affected by the molecule?substrate interaction. At the monolayer regime, the molecules can form a close-packed ordered structure. When the FePc goes further to the second layer, the unit cell of the formed molecular superstructure shifts compared with the unit cell of the first layer. Comparison of the growth behavior between the FePc and the CoPc also is made to understand the growth difference within the family of the phthalocyanine (Pc) molecules. And it is found that the central metal atom of the metal Pc makes a main contribution to the shift. Our results are helpful for understanding the growth of the Pc molecule family and controlling the related physical properties.