Search results for " thin films"

showing 10 items of 67 documents

Rhodamine (B) photocatalysis under solar light on high crystalline ZnO films grown by home-made DC sputtering

2018

Abstract ZnO thin films were deposited by home-made DC sputtering of zinc target under mixed gases (Argon, Oxygen) plasma on glass substrates. Films were deposited by varying oxygen partial pressure (PO2) from 0.09 to 1.3 mbar in the deposition chamber, at a fixed substrate temperature of 100 °C. The samples were characterized by photoluminescence (PL), X-ray diffraction (XRD), optical transmissions (UV–vis), scanning electron microscopy (SEM) and electrical (Hall effect) measurements. The results indicate that by varying the oxygen pressure in the deposition chamber, the films show a precise and well defined photoluminescence emissions for each range of pressure covering almost the entire …

010302 applied physicsMaterials sciencePhotoluminescenceZnO thin films Sputtering Photoluminescence Rhodamine (B) Solar light PhotocatalysisScanning electron microscopeBand gapAnalytical chemistry02 engineering and technologySubstrate (electronics)021001 nanoscience & nanotechnology01 natural sciencesSettore ING-INF/01 - ElettronicaAtomic and Molecular Physics and OpticsElectronic Optical and Magnetic Materialschemistry.chemical_compoundchemistrySputtering0103 physical sciencesPhotocatalysisRhodamine BElectrical and Electronic EngineeringThin film0210 nano-technology
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Single crystal-like thin films of blue bronze

2021

Abstract Pulsed laser deposition technique was employed to grow thin films of K 0.3 M o O 3 on A l 2 O 3 (1-102) and S r T i O 3 (510) substrates. Structural and imaging characterization revealed good quality films with well oriented grains of few microns in length. Both non-selective (transport) and order-selective (femtosecond pump-probe spectroscopy) probes revealed charge density wave properties that are very close to those of the single crystals. The films exhibit metal-semiconductor phase transition in resistivity, pump-probe data show phase transition at the same temperature as the single crystal and the threshold for the photo-induced phase transition is approximately the same as in…

010302 applied physicsPhase transitionMaterials scienceMetals and AlloysAnalytical chemistry02 engineering and technologySurfaces and Interfaces021001 nanoscience & nanotechnology01 natural sciencesSurfaces Coatings and FilmsElectronic Optical and Magnetic MaterialsPulsed laser depositionBlue bronze (BB) ; Charge density waves (CDW) ; Thin films ; Single crystal-like ; Ultrafast pump-probe spectroscopyElectrical resistivity and conductivity0103 physical sciencesFemtosecondMaterials ChemistryThin film0210 nano-technologySpectroscopySingle crystalCharge density waveThin Solid Films
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Correlation between in situ structural and optical characterization of the semiconductor-to-metal phase transition of VO2 thin films on sapphire

2020

A detailed structural investigation of the semiconductor-to-metal transition (SMT) in vanadium dioxide thin films deposited on sapphire substrates by pulsed laser deposition was performed by in situ temperature-dependent X-ray diffraction (XRD) measurements. The structural results are correlated with those of infrared radiometry measurements in the SWIR (2.5-5 μm) and LWIR (8-10.6 μm) spectral ranges. The main results indicate a good agreement between XRD and optical analysis, therefore demonstrating that the structural transition from monoclinic to tetragonal phases is the dominating mechanism for controlling the global properties of the SMT transition. The picture that emerges is a SMT tr…

010302 applied physicsPhase transitionMaterials scienceTransition temperatureAnalytical chemistryPulsed laser depositionphase change material; VO202 engineering and technologyVO2 thin films021001 nanoscience & nanotechnology01 natural sciencesSettore ING-INF/01 - ElettronicaPulsed laser depositionTetragonal crystal systemVO20103 physical sciencesSapphireThermal hysteresisGeneral Materials ScienceCrystalliteThin film0210 nano-technologyphase change materialMonoclinic crystal systemSemiconductor-to-metal (SMT) transition
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Electromagnetically induced switching of ferroelectric thin films

2007

We analyze the interaction of an electromagnetic spike (one cycle) with a thin layer of ferroelectric medium with two equilibrium states. The model is the set of Maxwell equations coupled to the undamped Landau-Khalatnikov equation, where we do not assume slowly varying envelopes. From linear-scattering theory, we show that low-amplitude pulses can be completely reflected by the medium. Large-amplitude pulses can switch the ferroelectric. Using numerical simulations and analysis, we study this switching for long and short pulses, estimate the switching times, and provide useful information for experiments.

010302 applied physicsPhysicsCondensed matter physicsScatteringNumerical analysisThin layerFOS: Physical sciencesPattern Formation and Solitons (nlin.PS)Condensed Matter Physics01 natural sciencesFerroelectricityNonlinear Sciences - Pattern Formation and SolitonsElectronic Optical and Magnetic Materialssymbols.namesakeAmplitudeMaxwell's equations0103 physical sciencessymbolsFerroelectric thin filmsThin film010306 general physicsComputingMilieux_MISCELLANEOUS
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Synthesis and Solution Processing of Nylon‐5 Ferroelectric Thin Films: The Renaissance of Odd‐Nylons?

2020

540 Chemistry and allied sciencesMaterials sciencePolymers and Plastics540 ChemieOrganic ChemistryPolymer chemistryMaterials ChemistryFerroelectric thin filmsThe RenaissancePhysical and Theoretical ChemistryComposite materialCondensed Matter PhysicsMacromolecular Chemistry and Physics
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Preparation and Characterization of Nanostructured Fe-TiO2 Thin Films Produced by Electrophoretic Deposition

2013

Fe-TiO2 thin films have been produced by a sol-electrophoretic deposition method on metallic Ti foil substrates. X-ray diffractograms and Raman spectra confirms the anatase structure of deposited and annealed Fe-TiO2 films. Obtained Fe-TiO2 thin films demonstrate photoactivity under visible light radiation due to the doping with Fe3+ ions. Open circuit potential results shows that increase of the film thickness and surface area improves the photoactivity of Fe-TiO2.

AnataseMaterials scienceTiO2 thin filmsDopingAnalytical chemistrysymbols.namesakeElectrophoretic depositionCarbon filmsymbolsDeposition (phase transition)sol-gelThin filmRaman spectroscopyphotoactivityFOIL methodelectrophoretic preparation
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Dissociative adsorption of water on Au/MgO/Ag(001) from first principles calculations

2015

Abstract The molecular and dissociative adsorption of water on a Ag-supported 1 ML, 2 ML and 3 ML-a six atomic layer-thick MgO films with a single Au adatom is investigated using density functional theory calculations. The obtained results are compared to a bulk MgO(001) surface with an Au atom. On thin films the negatively charged Au strengthens the binding of the polar water molecule due to the attractive Au–H interaction. The adsorption energy trends of OH and H with respect to the film thickness depend on an adsorption site. In the case OH or H binds atop Au on MgO/Ag(001), the adsorption becomes more exothermic with the increasing film thickness, while the reverse trend is seen when th…

Au adatomsExothermic reactionta114Chemistrydissociation of waterSurfaces and InterfacesDFT calculationsCondensed Matter PhysicsRedoxSurfaces Coatings and FilmsAdsorptionComputational chemistryAtomMaterials ChemistryCoulombadsorption of waterMoleculePhysical chemistryDensity functional theoryThin filmta116Ag-supported MgO thin filmsSurface Science
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A Simple Apparatus for the Determination of the Optical Constants and the Thickness of Absorbing Thin Films

2001

We report on a simple and inexpensive apparatus useful for measuring the optical constants n, k and the thickness of weakly absorbing thin films. The measurement is based on an accurate determination of the reflectance and transmittance of a specimen illuminated by a laser beam. The laser beam is incident on a transparent substrate coated with the film to be evaluated, with an angle of incidence equal to the Brewster angle for the substrate, and its polarization can be switched between the p and s states. If the thickness is known to be within a presumptive range, measurements of the p and s reflectance and transmittance allow a calculation of the optical constants n, k and the thickness of…

Brewster's angleMaterials sciencebusiness.industryPhysics::OpticsPolarization (waves)Layer thicknessReflectivityAtomic and Molecular Physics and OpticsElectronic Optical and Magnetic Materialssymbols.namesakeOpticssymbolsTransmittanceElectrical and Electronic EngineeringPhysical and Theoretical ChemistryThin filmbusinessOptical constants measurements Absorbing thin films Reflection and transmission coefficients ITO filmsLaser beams
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Surface Characterization of Organic Films for the Conservation of Bronze Archaeological Artefacts

2009

Bronze cancer thin films Artefact conservation Bronze passivation
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Morphological, electrical and optical properties of organic light-emitting diodes with a LiF/Al cathode and an Al-hydroxyquinoline/diamine junction

2004

Abstract We report the results of the morphological, electrical and optical characterisation of double-layer Alq3-based organic emitting diodes with a lithium fluoride (LiF)/Al cathode. A detailed electron microscopy investigation of their cross-section shows the presence of LiF isolated grains underneath the Al film. Due to the introduction of the LiF layer, luminance was larger than 30,000 cd/m2 at a bias voltage VB=25 V with a maximum external luminous efficiency as large as 46 lm/W at VB=20 V. Performing on/off VB cycles at a very low frequency, each time a recovery of the initial electric and luminous performance was observed. The non-exponential decay of both electric current and lumi…

ChemistryMechanical EngineeringMetals and AlloysAnalytical chemistryalq3; electroluminescence; organic diodes; thin filmsLithium fluorideBiasingElectroluminescenceCondensed Matter PhysicsCathodeElectronic Optical and Magnetic Materialslaw.inventionchemistry.chemical_compoundMechanics of MaterialslawMaterials ChemistryOLEDElectric currentLuminous efficacyDiode
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