The Experts below are selected from a list of 39552 Experts worldwide ranked by ideXlab platform
Federico Capasso - One of the best experts on this subject based on the ideXlab platform.
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controlled modification of erbium lifetime by near field coupling to Metallic Films
New Journal of Physics, 2009Co-Authors: Alexey Belyanin, Jiming Bao, Federico CapassoAbstract:Systematic measurements of the photoluminescence lifetime of the 1.54µm transition of erbium implanted at different energies in SiO2 Films with different Metallic overlayers are reported. The lifetime shows a strong reduction up to a factor of 20 with decreasing distance between the erbium and the metal overlayer. The reduction of lifetime is mainly due to a near-field interaction between the erbium ions and the metal overlayers through generation of surface plasmon polaritons at the metal/SiO2 interface and direct generation of heat in the metal. These experiments combined with rigorous theoretical modeling demonstrate that a high degree of control over the radiative properties of erbium can be achieved in erbium-implanted materials in a wide range of implantation energies. The experiments also allow us to determine the radiative efficiency of erbium in bulk SiO2. Contents
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observation of the skin depth effect on the casimir force between Metallic surfaces
Proceedings of the National Academy of Sciences of the United States of America, 2005Co-Authors: Mariangela Lisanti, Davide Iannuzzi, Federico CapassoAbstract:We have performed measurements of the Casimir force between a Metallic plate and a transparent sphere coated with Metallic Films of different thicknesses. We have observed that, if the thickness of the coating is less than the skin-depth of the electromagnetic modes that mostly contribute to the interaction, the force is significantly smaller than that measured with a thick bulk-like film. Our results provide direct evidence of the skin-depth effect on the Casimir force between Metallic surfaces.
Christophe Pijolat - One of the best experts on this subject based on the ideXlab platform.
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Applications of membranes and filtering Films for gas sensors improvements
Thin Solid Films, 2005Co-Authors: Christophe Pijolat, Jean-paul Viricelle, Guy Tournier, Pierre MontméatAbstract:It is possible to improve the performances of gas sensors using filtering Films déposited above the sensing marerial. This paper is a review of several rencent studies performed by the authors in this sense in order to point out the major dificulties on this subject. The difference between thin and thick film technologies is well underlined. Firstly, an example of thick porous layer is presented with the objective to develop a parous protective layer for soot protection in car exhausts. By another way, the use of Metallic Films has been successfully used to improve the selectivity of SnO2 sensors. Even if thin Films of rhodium allow to solve the problem of the dual response CO/NO2, the best results are obtained generally with thick Films. This is partly due to several problems resulting of the direct contact of the Metallic Films with the sensing material. The use of SiO2 thick insulating layer allows to improve the selectivity to CH4 with a fully agreement wirh catalytic activities of a platinium filter in regards the CO interference. Alast example demonstrates also the interest of thin SiO2 Films for the selective detection of H2.
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Selectivity improvement of SnO2 Films by superficial Metallic Films
Sensors and Actuators B: Chemical, 1999Co-Authors: Muriel Sauvan, Christophe PijolatAbstract:The purpose of this paper is to demonstrate the possibility of modifying the sensitivity of tin dioxide (SnO2) Films by depositing Metallic catalysts on the surface of SnO2 layer. The aim is to reduce the effect of ethanol which is considered as an interfering gas in many domestic or industrial applications. Two catalysts have been so studied (platinum and palladium), deposited on two types of SnO2 layers which present different textures. Both catalysts reduce the sensitivities to ethanol, carbon monoxide and methane. But the decrease of the alcohol sensitivity is more significant and consequently, the relative sensitivities to CO and CH4 are increased. This effect is more important with the SnO2 layers which have a high porosity. An other application where tin dioxide sensors can be used is the automotive application. In this case, nitrogen oxides are considered as interfering gases for the carbon monoxide detection. Several catalysts are studied in order to decrease the influence of nitrogen oxides and especially the conductance decrease under NO2. One of the catalysts which can be used to reduce the nitrogen oxide effect is rhodium. The results obtained with such rhodium Films deposited on SnO2 sensors allow us to consider future applications in the automotive field.
Bhushan Lal Karihaloo - One of the best experts on this subject based on the ideXlab platform.
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Size-dependent bending of thin Metallic Films
International Journal of Plasticity, 2008Co-Authors: Bhushan Lal KarihalooAbstract:Size-dependent large curvature pure bending of thin Metallic Films has been analytically studied taking into account the associated strengthening mechanisms at different thickness scales. The classical plasticity theory is applicable to Films thicker than 100 μm. Consequently, their bending capacity is governed by the competition between the material hardening and the thickness reduction. For Films with a thickness ranging from fractions of a micron to a few microns, in addition to the above mechanisms, the strain gradient effect plays an important role and introduces an internal length scale. When the film thickness reduces to the nano-scale, the strain gradient effect is gradually replaced by the dominant surface stress/energy effect.
F C Marques - One of the best experts on this subject based on the ideXlab platform.
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coefficient of thermal expansion and elastic modulus of thin Films
Journal of Applied Physics, 1999Co-Authors: M M De Lima, R G Lacerda, J Vilcarromero, F C MarquesAbstract:The coefficient of thermal expansion (CTE), biaxial modulus, and stress of some amorphous semiconductors (a-Si:H, a-C:H, a-Ge:H, and a-GeCx:H) and Metallic (Ag and Al) thin Films were studied. The thermal expansion and the biaxial modulus were measured by the thermally induced bending technique. The stress of the Metallic Films, deposited by thermal evaporation (Ag and Al), is tensile, while that of the amorphous Films deposited by sputtering (a-Si:H, a-Ge:H, and a-GeCx:H) and by glow discharge (a-C:H) is compressive. We observed that the coefficient of thermal expansion of the tetrahedral amorphous thin Films prepared in this work, as well as that of the Films reported in literature, depend on the network strain. The CTE of tensile Films is smaller than that of their corresponding crystalline semiconductors, but it is higher for compressive Films. On the other hand, we found out that the elastic biaxial modulus of the amorphous and Metallic Films is systematically smaller than that of their crystalline c...
St́phanie P. Lacour - One of the best experts on this subject based on the ideXlab platform.
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Microstructured silicone substrate for printable and stretchable Metallic Films
Langmuir, 2011Co-Authors: Adam P. Robinson, Ivan Minev, Ingrid M. Graz, St́phanie P. LacourAbstract:Stretchable electronics (i.e., hybrid inorganic or organic circuits integrated on elastomeric substrates) rely on elastic wiring. We present a technique for fabricating reversibly stretchable Metallic Films by printing silver-based ink onto microstructured silicone substrates. The wetting and pinning of the ink on the elastomer surface is adjusted and optimized by varying the geometry of micropillar arrays patterned on the silicone substrate. The resulting Films exhibit high electrical conductivity (∼11 000 S/cm) and can stretch reversibly to 20% strain over 1000 times without failing electrically. The stretchability of the ≥200 nm thick Metallic film relies on engineered strain relief in the printed film on patterned PDMS.