Coverage-dependent study of nickel tetraphenyl-porphyrin on Au(332) and Au(788)

The coverage-dependent self-assembly of Nickel-tetraphenyl porphyins on Gold vicinal surfaces was studied by scanning tunneling microscopy. On Au(788) the molecular self-assembly is square-shaped, following the molecular symmetry. On Au(332) the molecules nucleate in a parallelogram lattice for monolayer coverage and in a squared lattice for multilayer coverage. Depending on the vicinal surface the molecules adopt either a saddle shaped or a more planar conformation. The experiments demonstrate that crystallographic direction, terrace sizes and coverage are important in establishing different assembly geometries. (AU)