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53. Atomic-level mechanisms of magnesium oxidationSandra Gardonio, Mattia Fanetti, Matjaž Valant, Dmytro Orlov, 2016, objavljeni znanstveni prispevek na konferenci Opis: Magnesium has been recently becoming an increasingly popular material for various applications. However, excessive chemical reactivity, and oxidation rate in particular, is a major obstruction on the way of Mg to become widely adopted. A significant problem causing the lack of Mg reactivity control is insufficient understanding of mechanisms involved in the oxidation of magnesium surface. Herewith we present the investigation of atomic-level mechanisms of oxidation initiation and propagation in pure Mg. Namely, X-ray photoelectron spectroscopy at synchrotron Elettra was used as a surface sensitive direct method to determine the valence of Mg and O and the valence band states at the early stage of oxide formation over a principal, most densely packed, crystallographic plane (0001) in pure Mg. The mechanisms of oxygen adsorption on magnesium free surface followed by oxidation (i.e. initiation and kinetics of MgO formation) are clarified. Copyright © 2016 by The Minerals, Metals & Materials Society. All rights reserved. Ključne besede: Magnesium, Oxidation, Synchrotron radiation, X-ray photoelectron spectroscopy Objavljeno v RUNG: 25.08.2017; Ogledov: 5147; Prenosov: 0 Gradivo ima več datotek! Več... |
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55. Determination of petrophysical properties of sedimentary rocks by optical methodsDorota Korte, Dejan Kaukler, Mattia Fanetti, Humberto Cabrera, Efrain Daubronte, Mladen Franko, 2017, izvirni znanstveni članek Ključne besede: sedimentary rocks, beam deflection spectroscopy, grain size distribution, petrophysical
properties, chemical composition Objavljeno v RUNG: 06.02.2017; Ogledov: 4377; Prenosov: 0 Gradivo ima več datotek! Več... |
56. Photocatalytic degradation of gaseous toluene by using TiO2 nanoparticles immobilized on fiberglass clothMinoo Tasbihi, Ioana Cǎlin, Andraž Šuligoj, Mattia Fanetti, Urška Lavrenčič Štangar, 2017, izvirni znanstveni članek Ključne besede: Titanium dioxide, immobilization, toluene, fiberglass cloth, gaseous photocatalysis Objavljeno v RUNG: 25.01.2017; Ogledov: 4935; Prenosov: 0 Gradivo ima več datotek! Več... |
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58. Effect of gamma irradiation on Schottky-contacted vertically aligned ZnO nanorod-based hydrogen sensorSapana Ranwa, Surendra Singh Barala, Mattia Fanetti, Mahesh Kumar, 2016, izvirni znanstveni članek Opis: We report the impact of gamma irradiation on the performance of a gold Schottky-contacted ZnO nanorod-based hydrogen sensor. RF-sputtered vertically aligned highly c-axis-oriented ZnO NRs were grown on Si(100) substrate. X-ray diffraction shows no significant change in crystal structure at low gamma doses from 1 to 5 kGy. As gamma irradiation doses increase to 10 kGy, the single crystalline ZnO structure converts to polycrystalline. The photoluminescence spectra also shows suppression of the near-band emission peak and the huge wide-band spectrum indicates the generation of structural defects at high gamma doses. At 1 kGy, the hydrogen sensor response was enhanced from 67% to 77% for 1% hydrogen in pure argon at a 150 °C operating temperature. However, at 10 kGy, the relative response decreases to 33.5%. High gamma irradiation causes displacement damage and defects in ZnO NRs, and as a result, degrades the sensor's performance as a result. Low gamma irradiation doses activate the ZnO NR surface through ionization, which enhances the sensor performance. The relative response of the hydrogen sensor was enhanced by ∼14.9% with respect to pristine ZnO using 1 kGy gamma ray treatment. © 2016 IOP Publishing Ltd. Ključne besede: ZnO, nanorods, gamma irradiation, sensor Objavljeno v RUNG: 12.01.2017; Ogledov: 4282; Prenosov: 0 Gradivo ima več datotek! Več... |
59. THE MORPHOLOGY DEPENDENCE ON GROWTH PARAMETERS IN NANOSTRUCTURED SEMICONDUCTORSMiha Gunde, 2014, diplomsko delo Opis: Poly(3-hexylthiophene) (P3HT) is an organic semiconductor material that is widely studied in the photovoltaics and transistor fields of research. The polymer exhibits a relatively high charge carrier mobility when the molecules are ordered in a crystalline way. In this
case the material exhibits a fibril-like morphology, which is usually studied by atomic force microscopy (AFM). Previous studies show that blending P3HT with graphene can further improve the charge carrier transport properties of the film. In this experiment, the scanning electron microscope (SEM) has been chosen, due to its practical aspects such as speed of operation and ease of use. Three sets of samples have been analyzed, containing films made of P3HT+graphene blends at different concentrations. The aims of the experiment are:
i) to find good conditions for the observation of the morphology features of the film
ii) to perform a morphological analysis of the surface of three sets of samples containing both pure P3HT, and P3HT+graphene blend, and possibly to highlight correlation between morpholgy and the charge transport properties.
Surface analysis is done by detecting the secondary electron (SE) emission, which is sensitive to topographical features of the surface. Good observation conditions were established by coating the specimen with a thin layer of conductive coating, using a high energy beam (30 keV), and tilting the sample to an angle (30 ◦ ). In two out of three of the analyzed pure P3HT films, the presence of fibrilles indicated a possibly good charge mobility, which has
been confirmed by electrical measurements using time-of-flight photoconductivity method (TOF). The presence of graphene has only slightly modified morphology of the film. Features of graphene flakes, which lie flat in the film, have been observed such as flake edges and folds. The flakes are homogeneously dispersed in the film without forming any connected network. TOF measurements have shown an increase in mobility of the charge carriers in the P3HT+graphene film. Ključne besede: scanning electron microscope, organic semiconductor thin film, P3HT, graphene, morphology Objavljeno v RUNG: 01.12.2016; Ogledov: 6615; Prenosov: 168 Celotno besedilo (30,93 MB) |
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