The Self-organized Structure Of Metallo-organic Compound On Metal Surfaces

The adsorption behaviors of1,1’-ferrocenedicarboxylic acid molecules on Au(111), Cu(111), Cu(100) and Cu(110) metal surfaces have been investigated by ultrahigh vacuum scanning tunneling microscopy (UHV-STM) at room-temperature. Special attentions have been paid on the influences of the physical properties and surface symmetry of metal substrates on self-assembled structure.On Au(111) surface, the deposited ferrocenedicarboxylic acid molecules spontaneously form wheat-chain self-assembled structures with various in-plane orientations due to the intermolecular hydrogen bondings and van der waals force; On Cu(111), the deposited ferrocenedicarboxylic acid molecules form no ordered structures due to strong interactions between the molecules and the surface. These disordered molecules can be turned into linear-shaped structures with the same symmetry as the Cu(111) surface after annealing at170degree. The differences between the self-organized structures of ferrocenedicarboxylic acid molecules on the metal surfaces with the same symmetry reveals that the physical properties of the substrate plays an important role on formation of self-assembled structures. The more active the element of a single crystal is, the stronger interaction is present between the molecules and the surface.On Cu(100) surface, ferrocenedicarboxylic acid molecules form grape-chain structures along with the surface direction [] driven by intermolecularforce multi-hydrogen bonds between the neighbored molecules; on Cu(110) surface, the ferrocenedicarboxylic acid molecules are arranged into linear-shaped structures only along crystallographic orientation [110] of Cu(110) surface. The presence of various self-organized structures of ferrocenedicarboxylic acid molecules on copper substrates demonstrates that the self-assembled structures is determined by the symmetry of the substrate which has strong interaction with the molecules.Triangle-shape graphene has been grown on Cu(111) surface by thermal decomposition of ferrocenedicarboxylic acid molecules in an ultrahigh vacuum chamber. Triangle-shape graphene is a single-crystalline one-layer domain with zigzag edge structure. Graphene islands can extend up to17nm until the growth process is hindered by the edges of the atomic terraces.