Self-organization of CoPc-F16CuPc mixture with non-equal composition on Ag(100): From sub-monolayer to monolayer coverage

Abstract

We investigated, by scanning tunneling microscope, self-organization of bimolecular layers composed of 0.3 ML cobalt-phthalocyanine (CoPc) with various amount of hexadecafluoro copper phthalocyanine (F16CuPc) adsorbed on the Ag(100) surface kept at room temperature. The coexistence of ordered bimolecular (52×52)R45∘ chessboard-like phase with 2D bimolecular gas phase is observed for the total molecular coverage equal to 0.4 ML and 0.7 ML. A monomolecular (29×29)R22∘ F16CuPc, the bimolecular chessboard-like and a 2D bimolecular gas phases are found for the total molecular coverage of 0.9 ML. Density of 2D bimolecular gas phase increases with increasing amount of F16CuPc deposited on the surface until the critical coverage for F16CuPc is reached, what triggers appearance of monomolecular (29×29)R22∘ F16CuPc phase. Completing the monolayer by adding 0.1 ML of F16CuPcs results in the coexistence of the bimolecular chessboard-like structure with the pure monomolecular F16CuPc domains. The non-equal molecular deposition ratios induce various point defects in the bimolecular ordered structure. Termination of bimolecular ordered phase parallel to the <001> direction indicates the dominant component in the mixture deposited on the surface.