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International audience; CuO x-CeO 2-δ /Si thin films were elaborated by pulsed laser deposition. At the surface of all CuO x-CeO 2-δ thin films, Ce 4+ and Cu +1 ions were present. Depth profiles indicated that a Cu 2 O rich layer, roughly 40 nm thick, covered the CuO x-CeO 2−δ thin films. Apart from the copper enriched surface, the copper repartition in the thin films is highly inhomogeneous and two types of copper oxides, CuO and Cu 2 O, in form of rounded grains 20 nm were identified in the thin films. At least 10 at. % Cu seems to be inserted in the ceria lattice. Pure CeO 2 grains result from the deposition of tetrahedron-like nanoclusters followed by coalescence of (111) faces, and CuO x-CeO 2-δ grains from the deposition of cube-like nanoclusters followed by coalescence of (110) faces. The good catalytic performances of the CuO x-CeO 2-δ /Si thin films are due to active {100} ceria exposed facets covered by a Cu 2 O nanoparticles.

For organic molecular materials the definition of the condition of epitaxial growth has been subjected to several misconceptions and a great debate, leading in any case to less restrictive requirements than for inorganic materials. Here, the deposition of oligothiophene films by molecular beam epitaxy on properly grown organic single crystals is discussed and all-organic rigorous epitaxy demonstrated for both sub-monolayer and several-monolayer thick films. The possibility of growing all-organic nanostructures directly follows from these results. © 2006 Elsevier B.V. All rights reserved.

Two off-critical blends of poly(2-vinylpyridine) and polystyrene, 2:3 and 3:2 (w:w) PVP:PS, were spin-cast (with varied domain scale R) onto periodically (λ = 4 μm) patterned substrate. The pattern consisted of two alternating symmetric stripes: Au attracting PVP and neutral self-assembled monolayer. The resulting droplet-type morphologies were recorded with Scanning Force Microscopy and examined with integral geometry approach. PVP-rich islands of the 2:3 PVP:PS films form, for a wide R/λ range, strongly anisotropic morphologies. They show up, for R/λ ∼ 0.5, a weak λ/2-substructure of smaller PVP droplets in addition to the domains periodic with λ. The 3:2 blend exhibits morphologies with dominant λ-structure of PVP ribbons, which encircle PS droplets. For R/λ ∼ 0.5, smaller PS domains are also present but no λ/2-substructure is formed. The |χE|-values of droplet surface density are reduced, as compared to homogeneous substrate, for the 3:2 blend (with |χE| → 0 for R ∼ λ). This effect is absent for the 2:3 mixture.

Positioning nanostructures and functional molecules at surfaces and engineering their local coupling behavior is a key challenge in nanotechnology. The recently discovered BN nanomesh on the Rh(111) surface is a potential candidate to combine both properties, templating on the nanometer-scale and electronic decoupling. By means of low temperature scanning tunneling microscopy and spectroscopy experiments we demonstrate this advantageous combination for the case of Co nanoclusters, which can be ordered in a hexagonal nanoarray with a nearest neighbor distance of 3.2 nm on the BN nanomesh. The detection of a Coulomb gap of approximate to 160 meV proves the electronic decoupling of the clusters from the rhodium substrate. (C) 2008 Elsevier B.V. All rights reserved.