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

2000 ◽  
Vol 15 (8) ◽  
pp. 1811-1815 ◽  
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.

scholarly journals Flexible ZnO photoelectrode for photo electrochemical energy conversion

2021 ◽  
Author(s):  
T. Shiyani ◽  
Indrani Banerjee ◽  
Santosh K. Mahapatra ◽  
Asim K Ray
Keyword(s):  
Band Gap ◽  
Diffraction Pattern ◽  
Absorption Spectra ◽  
Optical Band Gap ◽  
Solar Fuels ◽  
Photoelectrochemical Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
A Value ◽  
Pet Substrate

Abstract Photoelectrochemical properties have been investigated for flexible ZnO/ITO/PET photoelectrodes. ZnO was spin coated on ITO/PET substrate with thickness of about 310 nm. The high crystalline structure of ZnO was studied using x-ray diffraction pattern. A value of 3.4 eV has been estimated for optical band gap from its absorption spectra. The flexible ZnO photoelectrode was demonstrated to generate photoelectrochemical current. Values of 1.022 and 0.714 were found to be for photo switching and photoresponsivity, respectively. ZnO/ITO/PET can be used as a substrate for making flexible hybrid PEC devices to generate solar power and solar fuels.

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

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.

scholarly journals Structural and electronic properties of the spinel Li4Ti5O12

2019 ◽  
Vol 20 (46) ◽  
pp. 7-12 ◽  
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.

scholarly journals Theoretical Prediction of the Structural and Electronic Properties of a Single Layer Graphene-like Two-dimensional Janus GaInSTe

2021 ◽  
Vol 37 (2) ◽  
Author(s):  
Nguyen Van Chuong ◽  
Nguyen Ngoc Hieu ◽  
Nguyen Van Hieu
Keyword(s):  
Electric Field ◽  
Band Gap ◽  
Electronic Properties ◽  
Single Layer ◽  
Single Layer Graphene ◽  
Two Dimensional ◽  
Direct Band Gap ◽  
Structural And Electronic Properties ◽  
Direct Band ◽  
New Type

This paper constructs a new type of two-dimensional graphene-like Janus GaInSTe monolayer and systematically investigates its structural and electronic properties as well as the effect of external electric field using first-principles calculations. In the ground state, Janus GaInSTe monolayer is dynamically stable with no imaginary frequencies in its phonon spectrum and possesses a direct band gap semiconductor. The band gap of Janus GaInSTe monolayer can be tuned by applying an electric field, which leads the different transitions from semiconductor to metal, and from indirect to direct band gap. These findings show a great potential application of Janus GaInSTe material for designing next-generation devices.

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

LACAME 2004 ◽  
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

Structural and electronic properties of indium-doped YBa2Cu3Oσ

1991 ◽  
Vol 6 (3) ◽  
pp. 446-449 ◽  
Author(s):  
Georg Weidlich ◽  
Michael Goelz ◽  
Ruiping Wang ◽  
William E. Evenson ◽  
John A. Gardner ◽  
...  
Keyword(s):  
Magnetic Flux ◽  
Electronic Properties ◽  
Solubility Limit ◽  
Formula Unit ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structural And Electronic Properties ◽  
Oxide Phases ◽  
Diffraction Patterns

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.

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

1986 ◽  
Vol 67 ◽  
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.

scholarly journals Some Thermomagnetic and Mechanical Properties of Amorphous Fe75Zr4Ti3Cu1B17 Ribbons

Materials ◽  
2022 ◽  
Vol 15 (1) ◽  
pp. 368
Author(s):  
Mariusz Hasiak ◽  
Jan Świerczek
Keyword(s):  
Single Phase ◽  
Entropy Change ◽  
X Ray Diffraction ◽  
X Ray ◽  
Field Induction ◽  
Average Value ◽  
A Value ◽  
Amorphous Ferromagnet ◽  
Instrumental Hardness ◽  
Magnetizing Field

The microstructure, revealed by X-ray diffraction and transmission Mössbauer spectroscopy, magnetization versus temperature, external magnetizing field induction and mechanical hardness of the as-quenched Fe75Zr4Ti3Cu1B17 amorphous alloy with two refractory metals (Zr, Ti) have been measured. The X-ray diffraction is consistent with the Mössbauer spectra and is characteristic of a single-phase amorphous ferromagnet. The Curie point of the alloy is about 455 K, and the peak value of the isothermal magnetic entropy change, derived from the magnetization versus external magnetizing field induction curves, equals 1.7 J·kg−1·K−1. The refrigerant capacity of this alloy exhibits the linear dependence on the maximum magnetizing induction (Bm) and reaches a value of 110 J·kg−1 at Bm = 2 T. The average value of the instrumental hardness (HVIT) is about 14.5 GPa and is superior to other crystalline Fe-based metallic materials measured under the same conditions. HVIT does not change drastically, and the only statistically acceptable changes are visibly proving the single-phase character of the material.

scholarly journals Size- and Temperature-control Optical Direct/indirect Band Tuning in Layered Compounds: Band Gap Engineering

2021 ◽  
Author(s):  
M. Miah
Keyword(s):  
Grain Size ◽  
Band Gap ◽  
Layered Compounds ◽  
Exciting Light ◽  
Interband Transitions ◽  
X Ray Diffraction ◽  
Band Gap Engineering ◽  
X Ray ◽  
Direct Band ◽  
Varshni Relation

Abstract The X-ray diffraction (XRD) is studied in thermally evaporated cadmium iodide (CdI2) thin films with various thicknesses. The grain size, calculated from the XRD, is found to increase with increasing the thickness of the film, while the reflectivity and refractive index decease with increasing the wavelength of the exciting light. The optical absorption spectra show both allowed direct and indirect interband transitions across a fundamental gap in CdI2. It is found that both indirect and direct band gap (Eg) decrease with increasing the thickness of the film and that the indirect Eg is lower than the direct Eg by an amount of about 0.7 eV. The direct Eg is also decreased with increasing both the grain size and temperature. However, the temperature dependence of Eg follows the Varshni relation. Our results highlight the possibility of engineering or tuning the Eg of CdI2 by controlling the thickness of the film, grain size as well as temperature.

scholarly journals Effect of Ag in CdSe thin films prepared using thermal evaporation

2017 ◽  
Vol 51 (12) ◽  
pp. 1656
Author(s):  
T.C.M. Santhosh ◽  
Kasturi V. Bangera ◽  
G.K. Shivakumar
Keyword(s):  
Thin Films ◽  
Band Gap ◽  
Thermal Evaporation ◽  
Hexagonal Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Glass Substrates ◽  
Potential Applications ◽  
Evaporation Technique ◽  
Transmission Measurements

It has been a general practice to dope thin films with suitable dopants to modify the properties of the films to make them more suitable for potential applications. When the dopant concentrations are low, they do not normally affect the structure and morphology of the films. However, it may lead to drastic changes in electronic properties of the films. This might result from the dopant getting incorporated into the lattice of the material of the films. Cadmium selenide is an important compound semiconductor material with an attractive energy band gap. The present work relates to an attempt made to dope CdSe thin films with silver. CdSe : Ag (1 to 5%) thin films were deposited on glass substrates at an optimized substrate temperature of 453 K using thermal evaporation technique. The grown films were analyzed using X-ray diffraction, scanning electron microscopy (SEM), energy dispersive analysis of X-ray (EDX) techniques. It is observed that undoped CdSe thin films and CdSe : Ag films have hexagonal structure. The grain size was found to increase marginally with an increase in the Ag concentration. The optical band gap of the films determined by optical transmission measurements agree with that of CdSe. Electrical conductivity is observed to increase from 10-4 to 3.66 (Omega ·cm)-1 on addition of silver. The variation of resistance with temperature indicates that the prepared films consist of CdSe and Ag existing as two separate phases coexisting and contributing individually to the resistivity of the films. DOI: 10.21883/FTP.2017.12.45181.8430

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