Structural and electronic properties of indium-doped YBa2Cu3Oσ

We have measured x-ray diffraction patterns and Meissner flux exclusion of YBa2Cu3Oσ containing indium. All samples were synthesized at temperatures near 940 °C, and the data indicate the indium atomic solubility to be approximately 3% per formula unit. At the solubility limit Tc is reduced from 92.7 K to 91.3 K relative to undoped samples, and the total magnetic flux excluded is reduced from approximately 40% to about 10%. For samples of formula InxY1−xBa2Cu3Oσ concentrations of other Y–Ba–Cu oxide phases are low and do not depend systematically on x. These results indicate that indium substitutes predominantly for yttrium when x is small.

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Structural and Electronic Properties of (CdTe)1−x(In2Te3)x Films Grown by Close-spaced vapor Transport Combined with Free Evaporation

Journal of Materials Research ◽

10.1557/jmr.2000.0261 ◽

2000 ◽

Vol 15 (8) ◽

pp. 1811-1815 ◽

Cited By ~ 2

Author(s):

M. Zapata-Torres ◽

Y. P. Mascarenhas ◽

M. A. Santana-Aranda ◽

J. Luyo-Alvarado ◽

M. Melé-Lirandez ◽

...

Keyword(s):

Band Gap ◽

Electronic Properties ◽

Single Phase ◽

Vapor Transport ◽

X Ray Diffraction ◽

X Ray ◽

A Value ◽

Structural And Electronic Properties ◽

Direct Band ◽

Transmission Measurements

The structural and electronic properties of (CdTe)1−x(In2Te3)x thin films as a function of substrate temperature were studied using x-ray diffraction, energy dispersive x-ray analysis, and Raman, transmission, and modulated transmission spectroscopies. The films were grown by the close-spaced vapor transport technique combined with free evaporation; CdTe and In2Te3 were used as sources. From x-ray diffraction the presence of mixed phases and differences in composition were detected, and good correlation with Raman spectroscopy was found. Transmission spectroscopy suggested the possibility of a modulation of the band gap of the alloy from a value as low as 0.5 eV up to 1.5 eV. Single-phase films presented a direct band gap of around 1.15 eV, as obtained from modulated transmission measurements.

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Properties of Pure and Sulfided NiMoO4 and CoMoO4 Catalysts: Tpr, Xanes and Time-Resolved XRD Studdzs

MRS Proceedings ◽

10.1557/proc-497-41 ◽

1997 ◽

Vol 497 ◽

Author(s):

S. Chaturvedi ◽

J. A. Rodriguez ◽

J. C. Hanson ◽

A. Albornoz ◽

J. L. Brito

Keyword(s):

Electronic Properties ◽

X Ray Diffraction ◽

Time Resolved ◽

Direct Transformation ◽

X Ray ◽

Β Phase ◽

Structural And Electronic Properties ◽

X Ray Absorption ◽

Kinetics Of ◽

Cobalt And Nickel

ABSTRACTX-ray absorption near-edge spectroscopy (XANES) was used to characterize the structural and electronic properties of a series of cobalt- and nickel-molybdate catalysts (AMoO4.nH20, α-AMoO4, β-AMoO4; A= Co or Ni). The results of XANES indicate that the Co and Ni atoms are in octahedral sites in all these compounds, while the coordination of Mo varies from octahedral in the a-phases to tetrahedral in the β-phases and hydrate. Time-resolved x-ray diffraction shows a direct transformation of the hydrates into the β-AMoO4 compounds (following a kinetics of first order) at temperatures between 200 and 350 °C. This is facilitated by the similarities that the AMoO4.nH20 and β-AMoO4 compounds have in their structural and electronic properties. The molybdates react with H 2 at temperatures between 400 and 600 °C, forming gaseous water and oxides in which the oxidation state of Co and Ni remains +2 while that of Mo is reduced to +5 or +4. After exposing α-NiMoO4 and P-NiMoO4 to H2S, both metals get sulfided and a NiMoSx phase is formed. For the β phase of NiMoO4 the sulfidation of Mo is more extensive than for the a phase, making the former a better precursor for catalysts of hydrodesulfurization reactions.

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Structural and electronic properties of the spinel Li4Ti5O12

Mongolian Journal of Chemistry ◽

10.5564/mjc.v20i46.1236 ◽

2019 ◽

Vol 20 (46) ◽

pp. 7-12 ◽

Cited By ~ 1

Author(s):

Sarantuya Lkhagvajav ◽

Namsrai Tsogbadrakh ◽

Enkhjargal Enkhbayar ◽

Sevjidsuren Galsan ◽

Pagvajav Altantsog

Keyword(s):

Electronic Properties ◽

First Principles ◽

Density Functional ◽

Experimental Studies ◽

First Principles Calculations ◽

X Ray Diffraction ◽

X Ray ◽

Structural And Electronic Properties ◽

Hubbard U ◽

Uv Visible

In this study, the structure and electronic properties of the spinel compound Li4Ti5O12 (LTO) are investigated both theoretical and experimental methods. The experimental studies of structural and electronic properties were performed by X-ray diffraction and UV-visible spectroscopy. The first principles calculations allowed to establish the relationship between the structure and electronic properties. The spinel type structure of LTO is refined by the Rietveld analysis using the X-ray diffraction (XRD). The band gap of LTO was determined to be 3.55 eV using the UV-visible absorption spectra. The Density functional theory (DFT) augmented without and with the Hubbard U correction (GGA and GGA +U+J0) is used to elucidate the electronic structure of LTO. We have performed systematic studies of the first principles calculations based on the GGA and GGA+U for the crystal structure and electronic properties of spinel LTO. We propose that a Hubbard U correction improves the DFT results.

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Structural and Electronic Properties Study of Colombian Aurifer Soils by Mössbauer Spectroscopy and X-ray Diffraction

LACAME 2004 ◽

10.1007/3-540-28960-7_7 ◽

2006 ◽

pp. 61-68

Author(s):

H. Bustos Rodríguez ◽

Y. Rojas Martínez ◽

D. Oyola Lozano ◽

G. A. Pérez Alcázar ◽

M. Fajardo ◽

...

Keyword(s):

Mössbauer Spectroscopy ◽

Electronic Properties ◽

Mossbauer Spectroscopy ◽

X Ray Diffraction ◽

X Ray ◽

Mößbauer Spectroscopy ◽

Structural And Electronic Properties

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MOCVD Growth of III-V Compounds on Si Using Strained Superlattices

MRS Proceedings ◽

10.1557/proc-67-15 ◽

1986 ◽

Vol 67 ◽

Cited By ~ 9

Author(s):

Shiro Sakai ◽

Tetsuo Soga ◽

Masanari Takeyasu ◽

Masayoshi Umeno

Keyword(s):

Electronic Properties ◽

Intermediate Layer ◽

Lattice Mismatch ◽

Gaas Layer ◽

X Ray Diffraction ◽

X Ray ◽

Double Heterostructure ◽

Si Substrates ◽

Mocvd Growth ◽

Structural And Electronic Properties

ABSTRACTGaAs and GaAsP with the entire compositional range are grow on Si using an intermediate layer of GaAsP strained superlattices to relax the lattice mismatch. The orientation of the overgrown GaAs layer is found to be determined by the direction of the off-angle of the Si (100) surface. The grown layers are characterized by photoluminescence, x-ray diffraction, electro reflectance and DLTS. GaAs/GaAlAs double heterostructure lasers and GaAsP visible LED's are fabricated on Si substrates. The structural and electronic properties of the grown layers and the device performances are reported in this paper.

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Investigation of Structural and Electronic Properties of CH3NH3PbI3 Stabilized by Varying Concentrations of Poly(Methyl Methacrylate) (PMMA)

Coatings ◽

10.3390/coatings7080115 ◽

2017 ◽

Vol 7 (8) ◽

pp. 115 ◽

Cited By ~ 5

Author(s):

Celline Awino ◽

Victor Odari ◽

Thomas Dittrich ◽

Pongthep Prajongtat ◽

Thomas Sakwa ◽

...

Keyword(s):

Electronic Properties ◽

Storage Time ◽

Impurity Phase ◽

X Ray Diffraction ◽

X Ray ◽

Structural And Electronic Properties ◽

The Stability ◽

Xrd Patterns ◽

Silicon Based ◽

Pl Quenching

Studies have shown that perovskites have a high potential of outdoing silicon based solar cells in terms of solar energy conversion, but their rate of degradation is also high. This study reports on improvement on the stability of CH3NH3PbI3 by passivating it with polymethylmethacrylate (PMMA). Structural and electronic properties of CH3NH3PbI3 stabilized by polymethylmethacrylate (PMMA) were investigated by varying concentrations of PMMA in the polymer solutions. Stability tests were performed over a period of time using modulated surface photovoltage (SPV) spectroscopy, X-ray diffraction (XRD), and photoluminescence (PL) measurements. The XRD patterns confirm the tetragonal structure of the deposited CH3NH3PbI3 for every concentration of PMMA. Furthermore, CH3NH3PbI3 coated with 40 mg/mL of PMMA did not show any impurity phase even after storage in air for 43 days. The Tauc gap (ETauc) determined on the basis of the in-phase SPV spectra was found in the range from 1.585 to 1.62 eV for the samples stored during initial days, but shifted towards lower energies as the storage time increased. This can be proposed to be due to different chemical reactions between CH3NH3PbI3/PMMA interfaces and air. PL intensity increased with increasing concentration of PMMA except for the perovskite coated with 40 mg/mL of PMMA. PL quenching in the perovskite coated with 40 mg/mL of PMMA can be interpreted as fast electron transfer towards the substrate in the sample. This study shows that, with an optimum concentration of PMMA coating on CH3NH3PbI3, the lifetime and hence stability on electrical and structural behavior of CH3NH3PbI3 is improved.

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Structural and Electronic Properties Study of Colombian Aurifer Soils by Mössbauer Spectroscopy and X-ray Diffraction

Hyperfine Interactions ◽

10.1007/s10751-005-9192-2 ◽

2005 ◽

Vol 161 (1-4) ◽

pp. 61-68 ◽

Cited By ~ 3

Author(s):

H. Bustos Rodríguez ◽

Y. Rojas Martínez ◽

D. Oyola Lozano ◽

G. A. Pérez Alcázar ◽

M. Fajardo ◽

...

Keyword(s):

Mössbauer Spectroscopy ◽

Electronic Properties ◽

Mossbauer Spectroscopy ◽

X Ray Diffraction ◽

X Ray ◽

Mößbauer Spectroscopy ◽

Structural And Electronic Properties

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Effect of Ni Doping on the MoS2 Structure and Its Hydrogen Evolution Activity in Acid and Alkaline Electrolytes

Surfaces ◽

10.3390/surfaces2040039 ◽

2019 ◽

Vol 2 (4) ◽

pp. 531-545 ◽

Cited By ~ 5

Author(s):

Dario Mosconi ◽

Paul Till ◽

Laura Calvillo ◽

Tomasz Kosmala ◽

Denis Garoli ◽

...

Keyword(s):

Electronic Properties ◽

Hydrogen Evolution ◽

Three Dimensional ◽

Linear Sweep Voltammetry ◽

Alkaline Media ◽

X Ray Diffraction ◽

Ni Doping ◽

X Ray ◽

Structural And Electronic Properties ◽

Alkaline Electrolytes

We have investigated three-dimensional (3D) MoS2 nanoarchitectures doped with different amount of Ni to boost the hydrogen evolution reaction (HER) in alkaline environment, where this reaction is normally hindered. As a comparison, the activity in acidic media was also investigated to determine and compare the role of the Ni sites in both media. The doping of MoS2, especially at high loadings, can modify its structural and/or electronic properties, which can also affect the HER activity. The structural and electronic properties of the Ni doped 3D-MoS2 nanoarchitecture were studied by X-ray diffraction (XRD), Raman spectroscopy, scanning and transmission electronic microscopy (SEM; TEM), and X-ray photoemission Spectroscopy (XPS). XPS also allowed us to determine the Ni-based species formed as a function of the dopant loading. The HER activity of the materials was investigated by linear sweep voltammetry (LSV) in 0.5 M H2SO4 and 1.0 M KOH. By combining the physicochemical and electrochemical results, we concluded that the Ni sites have a different role in the HER mechanism and kinetics in acidic and in alkaline media. Thus, NiSx species are essential to promote HER in alkaline medium, whereas the Ni-Mo-S ones enhance the HER in acid medium.

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Tungsten-Based Cost-Effective Gas Sensors for H2S Detection

Chemosensors ◽

10.3390/chemosensors9110295 ◽

2021 ◽

Vol 9 (11) ◽

pp. 295

Author(s):

Didier Fasquelle ◽

Nathalie Verbrugghe ◽

Stéphanie Députier

Keyword(s):

Dynamic Response ◽

Gas Sensors ◽

Rf Sputtering ◽

Cost Effective ◽

X Ray Diffraction ◽

Conduction Model ◽

X Ray ◽

Different Temperatures ◽

Oxide Phases ◽

Diffraction Patterns

Tungsten trioxide thin films were deposited on silicon substrates by non-reactive RF sputtering from a WO3 target at room temperature. The WO3 films were post-annealed at two different temperatures, 400 °C and 500 °C. The morphological and microstructural properties of these films were analyzed by using atomic force microscopy and X-ray diffraction. X-ray diffraction patterns only show WO3 oxide phases. The AFM images show different morphologies with smaller grains for the film annealed at 400 °C. WO3 sensing films and W heating elements were embedded in commercial cases for the fabrication of cost-effective gas sensors. The sensitivity and dynamic response of the sensors were analyzed under various concentrations of H2S, from 20 to 100 ppm, at SIMTRONICS SAS (3M Company, Saint Paul, MN, USA). A good sensitivity G/G0 of about 6.6 under H2S 100 ppm was obtained with the best sensor. An interesting dynamic response was observed in particular with a short response time. Additionally, the evolution of the sensitivity was studied, and a conduction model was proposed for explaining the conduction mechanism under H2S exposition.

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Structural and Electronic Properties of Pb/Cu Multilayers

MRS Proceedings ◽

10.1557/proc-160-599 ◽

1989 ◽

Vol 160 ◽

Cited By ~ 5

Author(s):

D. Neerinck ◽

K. Temst ◽

H. Vanderstraeten ◽

C. Van Haesendonck ◽

Y. Bruynseraede ◽

...

Keyword(s):

Electronic Properties ◽

Mean Free Path ◽

Diffraction Spectrum ◽

Superconducting Transition ◽

X Ray Diffraction ◽

Multilayered Structures ◽

X Ray ◽

Structural And Electronic Properties ◽

The Individual ◽

Interfacial Scattering

AbstractWe have performed extensive structural and electronic transport measurements of Pb/Cu multilayered structures. The high-angle x-ray diffraction spectrum indicates the presence of continuous interfacial disorder. In the low-angle x-ray spectrum, pronounced minima occur at positions given by q = 2π/Λ, where Λ is the bilayer thickness. This is in sharp contrast to the results for Pb/Ge (crystalline/amorphous) multilayers, where minima are observed at positions q = 2π / tPb with tPb the Pb thickness. These low-angle x-ray spectra can be explained by taking into account lateral coherence and continuously distributed thickness fluctuations. The effect of this interfacial disorder on the electronic properties is investigated by measuring the low-temperature resistivity and the superconducting transition temperature of the multilayers. The calculated values for the elastic mean free path in the individual layers confirm the presence of strong interfacial scattering. The thickness dependence of the critical temperature is explained by taking into account an interfacial barrier with penetration probability σ ≃ 0.5.

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