Search results for "Nitride"
showing 10 items of 249 documents
HMF Selective Photo-oxidation in Aqueous Suspension of Both Bare and H2O2 Treated Carbon Nitride Carried out in a Solar Pilot Plant
2018
HMF Selective Photo-oxidation in Aqueous Suspension of Both Bare and H2O2 Treated Carbon Nitride Carried out in a Solar Pilot Plant
Palladium clusters on BNNT as catalysts for biomass conversion
2015
The construction of a heterogeneous catalytic systems by a bottom-up approach is a fascinating strategy well assisted by molecular level characterizations. In this sense, DFT investigations can be used with predictive and descriptive purposes both for the treatment of the catalyst/support and for the substrate/catalyst characterization. This should be particularly useful for highly perspective but scarcely treated systems such as boron nitride based supports. Among these, boron nitride nanotubes (BNNT) have been demonstrated to have high chemical and thermal stability as well as great mechanical strength and high thermal conductivity.[1] Moreover, a high affinity toward hydrogen [2] as well…
Computational Investigation of Palladium Supported Boron Nitride Nanotube Catalysts
2015
A QM/MM investigation is reported dealing with the nucleation and growth of small palladium clusters, up to Pd8 , on the outer surface of a suitable model of boron nitride nanotube (BNNT). It is shown that the BNNT could have a template effect on the cluster growth, which is due to the interplay between Pd-N and Pd-Pd interactions as well as to the matching of the B3N3 ring and the Pd(111) face arrangement. The values for the clusters adsorption energies reveal a relatively strong physisorption, which suggests that in particular conditions the BNNTs could be used as supports for the preparation of shape-controlled metal cluster
Different preparation methods of bare and doped carbon nitride (C3N4) employed for selective photocatalytic oxidations
2018
Different preparation methods of bare and doped carbon nitride (C3N4) employed for selective photocatalytic oxidations
Determination of molecular stopping cross section of 12C, 16O, 28Si, 35Cl, 58Ni, 79Br, and 127I in silicon nitride
2015
Abstract Silicon nitride is a technologically important material in a range of applications due to a combination of important properties. Ion beam analysis techniques, and in particular, heavy ion elastic recoil detection analysis can be used to determine the stoichiometry of silicon nitride films, which often deviates from the ideal Si3N4, as well as the content of impurities such as hydrogen, even in the presence of other materials or in a matrix containing heavier elements. Accurate quantification of IBA results depends on the basic data used in the data analysis. Quantitative depth profiling relies on the knowledge of the stopping power cross sections of the materials studied for the io…
Sputtered SiOxNy thin films: improving optical efficiency of liquid crystal diffuser elements in multi-focal near-to-eye display architecture
2021
In this work we present reactive sputtered SiOxNy films with a variable refractive index as a convienent solution for contrast improvement of liquid crystal diffuser multi stacks in near-to-eye AR/VR displays. The focus concerns minimization of light reflections between internal structures, in particular ITO, by optimizing internal layers through tailored properties of thin film coatings, as well as subsequent laser patterning of thin film stack. Inorganic thin films have been deposited on glass by physical vapor deposition. Corresponding refractive index, thickness, uniformity and dielectric characteristics and other electro-optical properties have been measured and their impact on the res…
Changes in surface stress, morphology and chemical composition of silica and silicon nitride surfaces during the etching by gaseous HF acid
2007
Abstract HF acid attack of SiO2 and Si3N4 substrates is analyzed to improve the sensitivity of a sensor based on microcantilever. Ex situ analysis of the etching using XPS, SIMS and AFM show significant changes in the anisotropy and the rate of the etching of the oxides on SiO2 and Si3N4 surface. Those differences influence the kinetic evolution of the plastic bending deflection of the cantilever coated with SiO2 and Si3N4 layer, respectively. The linear dependence between the HF concentration and the Si3N4 cantilever bending corresponds to a deep attack of the layer whereas the non-linear behavior observed for SiO2 layer can be explained by a combination of deep and lateral etching. The ca…
Solar blind detectors based on AlGaN grown on sapphire
2005
Solar blind detectors have been fabricated based on AlGaN heterostructures grown on sapphire by molecular beam epitaxy or chemical vapour deposition. MSM and Schottky detectors were investigated. High performance devices have been obtained thanks to an optimization of the material crystalline quality (including the suppression of cracks) and of the process. We show that the spectral limitations of MSM detectors are dictated by intrinsic phenomena that are analysed in details while the responsivity and detectivity also depends on the technological process with a special emphasis on the geometry of finger and contact pads. One and two dimensional arrays have been fabricated and preliminary re…
Bundlet Model of Single- Wall Carbon, BC2N and BN Nanotubes, Cones and Horns in Organic Solvents
2013
Bundlet Model of Single- Wall Carbon, BC2N and BN Nanotubes, Cones and Horns in Organic Solvents The existence of Single-wall C-nanocones (SWNCs), especially nanohorns (SWNHs) and BC2N/Boron Nitride (BN) analogues is discussed in organic solvents in cluster form. A theory is developed based on the bundlet model, describing distribution function by size. The phenomena present unified explanation in the model, in which free energy of (BC2N/BN )SWNCs involved in cluster, is combined from two components: volume one proportional to the number of molecules n in cluster and surface one, to n1/2. The model enables describing distribution function of (BC2N/BN )SWNC clusters by size. From geometrical…
Microrefrigeration by quasiparticle tunnelling in NIS and SIS junctions
2000
Abstract A solid-state refrigeration method at sub-kelvin temperatures has been developed. It is based on quasiparticle tunnelling between a superconductor and a normal metal, or, between two dissimilar superconducting metals. The refrigerator is fabricated by combining nanolithography and micromachining methods. This technique has been demonstrated in both electron cooling from 0.3 to 0.1 K and in refrigeration of a dielectric platform. We describe a new fabrication method of tunnel junctions in a shadow evaporation configuration using a mechanical mask of silicon nitride.