Search results for " Electrochemical Impedance Spectroscopy"

showing 10 items of 24 documents

Physicochemical characterization of passive films on niobium by admittance and electrochemical impedance spectroscopy studies

2005

An analysis of the electronic properties of amorphous semiconductor-electrolyte junction is reported for thin (D ox < 20 nm) passive film grown on Nb in acidic electrolyte. It will be shown that the theory of amorphous semiconductor-electrolyte junction (a-SC/EI) both in the low band-bending and high band-bending regime is able to explain the admittance data of a-Nb 2 O 5 /El interface in a large range (10 Hz-10 kHz) of frequency and electrode potential values. A modelling of experimental EIS data at different potentials and in the frequency range of 0.1 Hz-100 kHz is presented based on the theory of amorphous semiconductor and compared with the results of the fitting of the admittance data…

AdmittanceChemistryGeneral Chemical EngineeringNiobiumAnalytical chemistrychemistry.chemical_elementphysicochemical characterization; semiconductor-electrolyte junction; electrochemical impedance spectroscopyElectrolyteAmorphous solidDielectric spectroscopysemiconductor-electrolyte junctionelectrochemical impedance spectroscopySettore ING-IND/23 - Chimica Fisica Applicataphysicochemical characterizationElectrochemistryDensity of statesElectrical impedanceElectrode potential
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Characterization of Thin Passive Film-Electrolyte Junctions. The Amorphous Semiconductor (a-SC) Schottky Barrier Approach.

2017

A detailed study of the electronic properties of thin (< 20 nm) anodic TiO2 potentiostatically grown on titanium in two different solutions is presented. The results show that the nature of the anodizing solution affects the electronic properties of the anodic film and in particular the density of electronic state (DOS) distribution. Different DOS were derived from the experimental data analyzed according to the theory of amorphous semiconductor (a-SC) Schottky barrier. It is shown that the usual non-linear and frequency dependent Mott-Schottky plots are in agreement with expected theoretical behaviour of a-SC Schottky barrier. It is shown the importance of the DOS distribution in determini…

Amorphous semiconductorsEngineeringSettore ING-IND/23 - Chimica Fisica Applicatabusiness.industrySchottky barrieranodic TiO2 Thin Passive Film Amorphous Semiconductor Electrochemical Impedance Spectroscopy electronic properties theory of amorphous semiconductor (a-SC) Schottky barrierElectrical engineeringOptoelectronicsElectrolytebusinessCharacterization (materials science)
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Archaeometric analysis of Roman bronze coins from the Magna Mater temple using solid-state voltammetry and electrochemical impedance spectroscopy

2017

Voltammetry of microparticles (VMP) and electrochemical impedance spectroscopy (EIS) techniques, complemented by SEM-EDX and Raman spectroscopy, were applied to a set of 15 Roman bronze coins and one Tessera from the temple of Magna Mater (Rome, Italy). The archaeological site, dated back between the second half and the end of the 4th century A.D., presented a complicated stratigraphic context. Characteristic voltammetric patterns for cuprite and tenorite for sub-microsamples of the corrosion layers of the coins deposited onto graphite electrodes in contact with 0.10 M HClO4 aqueous solution yielded a grouping of the coins into three main groups. This grouping was confirmed and refined usin…

CupriteSolid-statebronze; electrochemical impedance spectroscopy; Roman coins; voltammetry of microparticles; analytical chemistry; environmental chemistry; biochemistry; spectroscopyContext (language use)02 engineering and technologyengineering.material01 natural sciencesBiochemistryAnalytical ChemistryTemplemedicineEnvironmental ChemistryBronzeVoltammetrySpectroscopyGraphite electrodeRoman coinsChemistry010401 analytical chemistryMetallurgyvoltammetry of microparticles021001 nanoscience & nanotechnologybronze0104 chemical sciencesDielectric spectroscopyelectrochemical impedance spectroscopymedicine.anatomical_structurevisual_artengineeringvisual_art.visual_art_medium0210 nano-technologyAnalytica Chimica Acta
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Electrochemical fabrication of high k Al-Ta mixed oxides

2014

Electrochemical fabrication high k Al-Ta mixed oxides Photoelectrochemistry Electrochemical Impedance Spectroscopy Tuning of solid state propertiesSettore ING-IND/23 - Chimica Fisica Applicata
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ELECTROCHEMICAL FABRICATION OF METAL/OXIDE/CONDUCTING POLYMER JUNCTIONS FOR ELECTRONIC DEVICES

2014

Electrochemical fabrication metal/oxide/conducting polymer junctions electronic devicesSettore ING-IND/23 - Chimica Fisica ApplicataSOLID STATE ELECTROLYTIC CAPACITORS FIELD EFFECT TRANSISTORS ANODIC OXIDES CONDUCTING POLYMERS PHOTOELECTROCHEMISTRY ELECTROCHEMICAL IMPEDANCE SPECTROSCOPY PEDOT NIOBIUM OXIDE TITANIUM OXIDE TANTALUM OXIDE
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Synergistic Use of Electrochemical Impedance Spectroscopy and Photoelectrochemical Measurements for Studying Solid State Properties of Anodic HfO2

2017

Within the past years, intense research has been carried out on HfO2 as high k material, promising candidate to replace SiO2 as gate dielectric in CMOS based devices (1), and as metal oxide for resistive random access memory (ReRAM) (2). For both technological applications compact, uniform and flat oxides are necessary, and a detailed understanding of their physical properties as a function of the fabrication conditions is strongly. Hafnia performance can be significantly influenced by carrier trapping taking place at pre-existing precursors states (induced by oxygen vacancies, interstitial ions, impurities acting as dopants), or by self-trapping in a perfect lattice, where the potential we…

EngineeringSettore ING-IND/23 - Chimica Fisica Applicataanodizing HfO2 CMOS ReRAM Electrochemical Impedance Spectroscopy Photoelectrochemical Measurements Solid State Propertiesbusiness.industrySolid-stateAnodizing Hafnium oxide Nb doped HfO2 Electrochemical Impedance Spectroscopy Photocurrent Spectroscopy Solid State Properties CMOS ReRAMNanotechnologybusinessAnodeDielectric spectroscopy
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Electrochemical discrimination of manufacturing types of pottery from Magna Mater Temple and Fora of Nerva and Caesar (Rome, Italy)

2018

Abstract The voltammetry of immobilized microparticles (VIMP) methodology is applied to a series of pottery samples from the Roman sites of Nerva's Forum (second half of 9th-early 11th A.D), Caesar's Forum (second half of 9th-early 11th A.D) and Magna Mater Temple (III century). The VIMP sampling applied to voltammetric and electrochemical impedance spectroscopy (EIS) measurements was applied by the first time to acquire archaeometric information on archaeological pottery. VIMP measurements using pressed sample pellets on gold electrodes in contact with air-saturated 0.10 M H2SO4 have permitted to detect voltammetric signals for the reduction/oxidation of Fe and Mn minerals as well as catal…

Materials scienceMetallurgy020101 civil engineeringGeology02 engineering and technology021001 nanoscience & nanotechnologyElectrochemistry0201 civil engineeringDielectric spectroscopyarchaeometry; electrochemical impedance spectroscopy; pottery; solid state voltammetry; geology; geochemistry and petrologymedicine.anatomical_structureGeochemistry and PetrologyTemplemedicineOxygen reduction reactionArchaeological potteryPottery0210 nano-technologyVoltammetryGraphite electrodeApplied Clay Science
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Enhancement of photoconversion efficiency in dye-sensitized solar cells exploiting pulsed laser deposited niobium pentoxide blocking layers

2015

Abstract Among all the photovoltaic technologies developed so far, dye-sensitized solar cells are considered as a promising alternative to the expensive and environmentally unfriendly crystalline silicon-based solar cells. One of the possible strategies employed to increase their photovoltaic efficiency is to reduce the charge recombination at the cell conductive substrate through the use of a compact blocking layer. In this paper, we report on the fabrication and characterization of dye-sensitized solar cells employing niobium pentoxide (Nb 2 O 5 ) thin film blocking layer deposited through the pulsed laser deposition technique on conductive substrates. The careful selection of the optimal…

Materials scienceOpen circuit voltage decaySubstrate (electronics)Dye-sensitized solar cellsSettore ING-INF/01 - ElettronicaPulsed laser depositionBlocking layer; Dye-sensitized solar cells; Electrochemical impedance spectroscopy; Niobium pentoxide; Open circuit voltage decay; Pulsed laser deposition; Electronic Optical and Magnetic Materials; Materials Chemistry; 2506; Metals and Alloys; 2506; Surfaces Coatings and Films; Surfaces and InterfacesCoatings and Filmschemistry.chemical_compoundElectronicMaterials ChemistryOptical and Magnetic MaterialsCrystalline siliconThin filmNiobium pentoxidepulsed laser depositionbusiness.industryOpen-circuit voltagePhotovoltaic systemMetals and AlloysSurfaces and InterfacesSurfaces Coatings and FilmsElectronic Optical and Magnetic MaterialsSurfacesDye-sensitized Solar CellDye-sensitized solar cellniobium pentoxidechemistryblocking layerOptoelectronics2506businessElectrochemical impedance spectroscopyThin Solid Films
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The Effect of Nb Incorporation on the Electronic Properties of Anodic HfO2

2017

Hafnium oxide and Nb doped HfO2 were grown by anodizing sputtering-deposited Hf and Hf-4at.%Nb. Photoelectrochemical characterization was carried out in order to estimate solid state properties such as band gap, flat band potential and electrons internal photoemission threshold energy as a function of thickness and composition of anodic oxides. Optical transitions at energy lower than the band gap value of the investigated anodic films were evidenced, and they are attributed to optical transitions involving localized states inside the band gap. Such states were located at 3.6 eV and 3.9 eV below the conduction band edge for the Nb free and Nb containing hafnium oxide, respectively. Impedanc…

Materials scienceSettore ING-IND/23 - Chimica Fisica ApplicataChemical engineeringAnodic oxides Electrochemical Impedance Spectroscopy HfO2 Nb incorporation Photoelectrochemistry02 engineering and technology010402 general chemistry021001 nanoscience & nanotechnology0210 nano-technology01 natural sciences0104 chemical sciencesElectronic Optical and Magnetic MaterialsElectronic propertiesAnode
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Photoelectrochemical Evidence of Cu2O/TiO2 Nanotubes Hetero-Junctions formation and their Physicochemical Characterization

2014

Cu2O/TiO2 nanotubes heterojunctions were fabricated by electrochemical deposition of cuprous oxide on TiO2 nanotubes arrays grown by anodizing. X-ray diffraction and Raman Spectroscopy analysis allows for identification of Cu2O, whose morphological features were studied by Scanning Electron Microscopy as a function of the charge circulated during the electrodeposition step. Photoelectrochemical measurements in aqueous solutions evidenced a red shift of the light absorption threshold of TiO2 nanotubes due to the presence of cuprous oxide even for very low circulated charges, while electrochemical impedance measurements proved a significant reduction of the electrode impedance due the presenc…

PhotocurrentMaterials scienceAqueous solutionCu2O/TiO2 nanotubes heterojunctions electrochemical fabrication XRD Raman Spectroscopy Photoelectrochemical measurements Electrochemical Impedance SpectroscopyAnodizingScanning electron microscopeGeneral Chemical EngineeringAnalytical chemistryOxideHeterojunctionElectrochemistrychemistry.chemical_compoundsymbols.namesakeSettore ING-IND/23 - Chimica Fisica ApplicataChemical engineeringchemistryElectrochemistrysymbolsRaman spectroscopyElectrochimica Acta
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