References of "Dubreuil, Olivier"
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See detailPIXE identification of the provenance of ferruginous rocks used by Neanderthals
Mathis, François ULg; Bodu, Pierre; Dubreuil, Olivier ULg et al

in Nuclear Instruments & Methods in Physics Research. Section B, Beam Interactions with Materials and Atoms (in press)

Les Bossats, near Ormesson, France, is a newly discovered late Mousterian open air site dated to around 47,000 years ago by thermoluminescence. The archaeological level, fossilized by loess, revealed a ... [more ▼]

Les Bossats, near Ormesson, France, is a newly discovered late Mousterian open air site dated to around 47,000 years ago by thermoluminescence. The archaeological level, fossilized by loess, revealed a rich industry based on the discoid mode, associated with numerous fragments of red and yellow iron oxide-rich rocks showing clear traces of powder production (abrasion, striation, scraping), which are exceptional remains for this remote period. Archeological material and geological samples from the close environment were studied by PIXE and by petrographical observations made on thin sections. The geological sources were identified by means of PIXE analyses on two IBA facilities: AGLAE (2 MV tandem) at the C2RMF in Paris and the cyclotron of the IPNAS (University of Liège). We paid particular attention to the comparison of results obtained on both installations by using the same set of geological standards and by a fine evaluation of the limit of detection relative to each trace elements of interest for both experimental set ups. The elemental fingerprint of one geological source of iron-rich concretions corresponds clearly with the archaeological collection. At least, this investigation demonstrates that the colouring materials were minutely selected in the close neighbouring of the site by the Neanderthals. [less ▲]

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See detailTiO2 mesoporous thin films studied by Atmospheric Ellipsometric Porosimetry: A case of contamination
Dubreuil, Olivier ULg; Dewalque, Jennifer ULg; Chene, Grégoire ULg et al

in Microporous and Mesoporous Materials (2011), 147

Anatase mesoporous TiO2 thin films are frequently prepared by surfactant templating to control porosity development and Atmospheric Ellipsometric Porosimetry is a reliable and fast technique allowing the ... [more ▼]

Anatase mesoporous TiO2 thin films are frequently prepared by surfactant templating to control porosity development and Atmospheric Ellipsometric Porosimetry is a reliable and fast technique allowing the determination of the porosity of such films. After prolonged exposition to high-vacuum (6×10-6 mbar), the films porosity exhibits a degraded behavior during porosimetric measurements, indicating a vacuum-induced modification. The main effect resulting from such exposition to high-vacuum is a wet- tability modification of the films, resulting in an increase of the hydrophobic character of the TiO2 surface. This evolution induces non-correct results in porosimetric measurements due to the fact that the contact angle parameter needed to calculate the pore size distribution is highly different from the reference films. A surface contamination explains such modifications and a restoration of the films is obtained by using ultraviolet treatment. [less ▲]

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See detailTiO2 multilayer thick films (up to 4 μm) with ordered mesoporosity: Influence of template on the film mesostructure and use as high efficiency photoelectrode in DSSCs
Dewalque, Jennifer ULg; Cloots, Rudi ULg; Mathis, François ULg et al

in Journal of Materials Chemistry (2011), 21(20), 7356-7363

Mesoporous templated anatase thin films are very promising materials to act as photoelectrode in dye-sensitized solar cell. Templated-assisted dip-coating techniques are used to obtain thin films with ... [more ▼]

Mesoporous templated anatase thin films are very promising materials to act as photoelectrode in dye-sensitized solar cell. Templated-assisted dip-coating techniques are used to obtain thin films with ordered porosity. However, monolayer films are very thin and suffer from a low quantity of active material, leading to poor photovoltaic performances. In this paper, a dip-coating-based multilayer deposition technique is reported. First, we have studied the influence of the template on the film organization and porosity in terms of long-range order, percentage of porosity, pore size and pores connectivity. Different techniques such as transmission electron microscopy (TEM), atmospheric poroellipsometry (AEP) and UV-visible absorption spectroscopy (UV-vis.) have been used to describe the microstructural features of the films with a thickness of 1 µm. The film exhibiting the highest dye loading was selected and its thickness gradually increased up to 4 µm. Finally, the photovoltaic performances of the thick films (1 to 4 µm) have been evaluated in combination with the N-719 dye and show excellent efficiency (6.1%) when compared to values reported in the literature. Such mesostructured films are compared in terms of photovoltaic performance with TiO2 nanoparticles films, generally used in DSSC. [less ▲]

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See detailCharacterization and impact of reduced copper plating overburden on 45 nm interconnect performances
Dubreuil, Olivier ULg; Caubet-Hilloutou, Véronique; Guillan, Julie et al

in Microelectronic Engineering (2010, March), 87(3),

During first metal level interconnects fabrication, a controlled modification of the electro-deposited copper over-deposition (overburden) is performed using a partial chemical–mechanical polishing (CMP ... [more ▼]

During first metal level interconnects fabrication, a controlled modification of the electro-deposited copper over-deposition (overburden) is performed using a partial chemical–mechanical polishing (CMP) step. Next, copper microstructure is stabilized with a short duration hot-plate anneal. Overburden is then removed during CMP end-of-step. Ionic microscopy and EBSD observations of overburden thickness reduction reveal that copper grain growth occurs differently, according to patterned geometries and with a strong (1 1 1) texture, as observed in modified films. Reduction of overburden thickness also reveals the capacity of anneal temperature to impact electrical performances. Reliability is impacted for thinnest wires. [less ▲]

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See detailCharacterization of copper grain growth limitations inside narrow wires depending of overburden thickness
Dubreuil, Olivier ULg; Cordeau, Maryline; Mourier, Thierry et al

in Microelectronic Engineering (2008, October), 85(10), 1988-1991

With the downscaling of feature dimensions, copper interconnects exhibit properties differing from bulk or film material. Resistivity increases and limits electrical performances, and reliability of ... [more ▼]

With the downscaling of feature dimensions, copper interconnects exhibit properties differing from bulk or film material. Resistivity increases and limits electrical performances, and reliability of interconnects becomes a more important challenge for each new technological node. In this study, we present an approach of copper grain growth control inside narrow wires by adding a step between the copper electro-chemical deposition (ECD) and the chemical–mechanical polishing (CMP). This step corresponds to a partial CMP step (pre-CMP) and is applied after ECD and before anneal in order to modify the copper previous termoverburdennext term thickness. Depending on the targeted thickness, copper grain growth occurs during anneal with different efficiencies. Crystallization and grain growth behavior inside wires is investigated with focused ions beam (FIB). We present here our methodology for sample preparation and characterization. Results are focused on electrical variations and on morphological aspects of copper crystallization and grain growth inside lines observed with various overburden thicknesses. [less ▲]

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See detailCoupled PIXE and RBS using a 6MeV 4He2+ external beam: a new experimental device for particle detection and dose monitoring.
Mathis, François ULg; Moignard, Brice; Pichon, Laurent et al

in Nuclear Instruments & Methods in Physics Research. Section B, Beam Interactions with Materials and Atoms (2005), 240

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