The Effect of Composition on the Properties of Semiconducting Transition Metal Nitrides

AbstractUsing the full potential linearized augmented plane wave (FP-LAPW) method, we investigate the bulk structural and electronic properties in the scandium-, yttrium-, and copper-nitrides over a wide range of nitrogen concentrations. The N atom was gradually incorporated into metal matrix with and without metal vacancies. The ground state properties like densities of states (DOS) and formation energies are determined for each calculated alloy. We have found that the semi-conducting state in copper nitride have a tinny compositional margin. Any deviation of the ideal stoichiometry will produce a metallic character. What is more, the stabilities of the conductive phases are very close to the stability of the semi conducting phase, with a little margin favorable to the conducting phases. The calculations of scandium- and yttrium nitrides show, that for very low nitrogen incorporations, the hexagonal and fcc phases may coexist. However, for high nitrogen concentration the cubic phases are favored. For non-stoichiometric nitrogen content, the materials behave as metal, whereas at stoichiometric composition the DOS becomes zero at Fermi level (EF), confirming in this way the semiconductor character of these nitrides.

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Titanium Dioxide – A Missing Photo-Responsive Material for Solar-Driven Oil Spill Remediation

10.5772/intechopen.98631 ◽

2021 ◽

Author(s):

Haruna Adamu

Keyword(s):

Titanium Dioxide ◽

Oil Spill ◽

Material Properties ◽

Photocatalytic Decomposition ◽

Full Potential ◽

Wide Range ◽

Structural And Electronic Properties ◽

Technical Details ◽

Photocatalytic Applications ◽

Oil Spill Remediation

TiO2 nanoparticles have been extensively investigated for environmental applications, particularly in the photocatalytic decomposition of organic pollutants using solar energy. The TiO2-derived photocatalysts attract attention because of their photocatalytic efficiency and activity under a wide range of environmental conditions in response to superior structural and electronic properties. Consequently, TiO2 compares with other common semiconductors used for environmental photocatalytic applications, TiO2 is widely being considered close to an ideal semiconductor for photocatalysis. However, despite the impressive photocatalytic and material properties of titanium dioxide, TiO2 has not to this point been incorporated within commercial hub of oil spill remediation products. Therefore, this chapter covers the description of inevitable technical details required for unveiling the full potential of solar-driven photooxidation potency of TiO2, which have been the major challenges that halt its translation to commercial use in oil spill remediation. This at the end would underpin and make TiO2-derived materials a substitute ready to be commercially accepted as a promising method for remediation of oil-polluted aquatic and soil environments.

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A Theoretical Analysis of Physical Properties and Half-Metallic Stability under Pressure Effect of the ScNiCrZ (Z=Ga, Al, In) Heusler Alloys

SPIN ◽

10.1142/s2010324721500077 ◽

2021 ◽

pp. 2150007

Author(s):

I. E. Rabah ◽

H. Rached ◽

M. Rabah ◽

D. Rached ◽

N. Benkhettou

Keyword(s):

Heusler Alloys ◽

Ferromagnetic Behavior ◽

Full Potential ◽

Half Metallicity ◽

Half Metallic ◽

Lattice Constants ◽

Wide Range ◽

Quaternary Heusler Alloys ◽

Lmto Method ◽

The Stability

The aim purpose of this study is to investigate the structural, elastic, magnetic, electronic properties and half-metallic stability under pressure of ScNiCrZ ([Formula: see text], Ga and In) quaternary Heusler alloys using full-potential linear muffin-tin orbital (FP-LMTO) method within the gradient generalized approximation (GGA) for exchange, and correlation potential. In order to evaluate the stability of our compounds, the formation energy, and elastic constants have been evaluated. The results showed that our compounds have ferromagnetic ground states and are energetically more stable in type-[Formula: see text] configuration. True half-metallic ferromagnetic behavior with 100% spin polarization at Fermi level [Formula: see text] with high Curie temperature [Formula: see text], and very interesting bandgap in the minority spin are obtained for the three alloys. The calculated total magnetic moment [Formula: see text] for all three alloys is consistent with Slater[Formula: see text]Pauling rule. The half-metallicity is maintained over a wide range of lattice constants making these alloys promising for spintronic, and magneto-electronics applications.

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FIRST STAGE OF THE FORMATION OF SILVER THIN FILMS ON THE As-PASSIVATED Si(111)-(1×1) SURFACE

Surface Review and Letters ◽

10.1142/s0218625x00000221 ◽

2000 ◽

Vol 07 (01n02) ◽

pp. 167-173 ◽

Cited By ~ 1

Author(s):

J. E. BONNET ◽

M. G. MARTIN ◽

J. AVILA ◽

L. ROCA ◽

M. C. ASENSIO

Keyword(s):

Photoelectron Spectroscopy ◽

Semiconductor Surface ◽

Silver Deposition ◽

Flat Interface ◽

Wide Range ◽

Structural And Electronic Properties ◽

Synchrotron Light ◽

Valence Bands ◽

The Stability ◽

The One

The As-terminated Si surface has an ideally flat monolayer of As atoms at the outermost layer, showing a nonreconstructed (1×1) symmetry with one extra valence electron on each As atom, and setting a passivation, on the silicon surface, remarkable for its stablity up to temperatures above 600°C and under Ag deposition. Angle-resolved photoelectron spectroscopy (ARUPS) of valence bands in the main Brillouin zone directions of the As–Si(111) surface, and X-ray photoelectron diffraction (XPD), recorded with the LURE synchrotron light, provide the principal results presented in this work. No arsenic diffusion into the metallic overlayer is detected by photoemission, in a wide range of temperatures, proving the stability of the Ag/As–Si(111) interface, and allowing a first study of the structural and electronic properties of this flat interface. The formation of the silver–metal films on the semiconductor surface has been investigated, in particular the growth mode in the one-monolayer range and the building of the semiconductor–metal interface, and the evolution of the film during the silver deposition up to a few monolayers.

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A study on structural and electronic properties of GaAs1-xNx and GaAs1-xBix alloys

International Journal of Physical Research ◽

10.14419/ijpr.v4i1.5775 ◽

2016 ◽

Vol 4 (1) ◽

pp. 6

Author(s):

Metin Aslan ◽

Battal Gazi Yalcin

Keyword(s):

Electronic Properties ◽

Density Functional ◽

Local Density ◽

Nitrogen Concentration ◽

Potential Method ◽

Generalized Gradient ◽

Wide Range ◽

Structural And Electronic Properties ◽

Semiconductor Alloy ◽

Ternary Semiconductor

We have performed first principles method to investigate structural and electronic properties of GaAs1-xNx and GaAs1-xBix ternary semiconductor alloy using Density Functional Theory and pseudo potential method within the Generalized Gradient Approximations and Local Density Approximation. The Zinc-Blende phase is found stable for GaAsN and GaAsBi alloys. In this study we investigate the both bowing parameters changing with Bismuth concentration in GaAsBi and Nitrogen concentration in GaAsN alloys. By using the bowing parameter of GaAsBi and GaAsN alloys we obtained the bandgap energies for all x concentrations (0 < x < 1) and lattice constant of both alloys which are important for wide range device application. For studied materials, lattice parameters and band gap energies are compared with available theoretical and experimental works.

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Recent Applications of High Resolution Electron Microscopy to Crystalline Arrays of Virus Particles

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100070199 ◽

1978 ◽

Vol 36 (3) ◽

pp. 470-482 ◽

Cited By ~ 1

Author(s):

R.W. Horne

Keyword(s):

Electron Microscopy ◽

Image Processing ◽

Analytical Techniques ◽

Staining Technique ◽

High Resolution Electron Microscopy ◽

Optical Diffraction ◽

Full Potential ◽

Virus Particles ◽

Resolution Electron ◽

Wide Range

The technique of surrounding virus particles with a neutralised electron dense stain was described at the Fourth International Congress on Electron Microscopy, Berlin 1958 (see Home & Brenner, 1960, p. 625). For many years the negative staining technique in one form or another, has been applied to a wide range of biological materials. However, the full potential of the method has only recently been explored following the development and applications of optical diffraction and computer image analytical techniques to electron micrographs (cf. De Hosier & Klug, 1968; Markham 1968; Crowther et al., 1970; Home & Markham, 1973; Klug & Berger, 1974; Crowther & Klug, 1975). These image processing procedures have allowed a more precise and quantitative approach to be made concerning the interpretation, measurement and reconstruction of repeating features in certain biological systems.

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Performance of Electronic Structure Methods for the Description of Hückel-Möbius Interconversions in Extended π-Systems

10.26434/chemrxiv.10564115 ◽

2019 ◽

Author(s):

Tatiana Woller ◽

Ambar Banerjee ◽

Nitai Sylvetsky ◽

Xavier Deraet ◽

Frank De Proft ◽

...

Keyword(s):

Electronic Structure ◽

Basis Set ◽

Dft Methods ◽

Molecular Switching ◽

Wide Range ◽

Electronic Structure Methods ◽

Explicitly Correlated ◽

Relative Errors ◽

The Stability ◽

Basis Set Expansion

Expanded porphyrins provide a versatile route to molecular switching devices due to their ability to shift between several π-conjugation topologies encoding distinct properties. Taking into account its size and huge conformational flexibility, DFT remains the workhorse for modeling such extended macrocycles. Nevertheless, the stability of Hückel and Möbius conformers depends on a complex interplay of different factors, such as hydrogen bonding, p···p stacking, steric effects, ring strain and electron delocalization. As a consequence, the selection of an exchange-correlation functional for describing the energy profile of topological switches is very difficult. For these reasons, we have examined the performance of a variety of wavefunction methods and density functionals for describing the thermochemistry and kinetics of topology interconversions across a wide range of macrocycles. Especially for hexa- and heptaphyrins, the Möbius structures have a pronouncedly stronger degree of static correlation than the Hückel and figure-eight structures, and as a result the relative energies of singly-twisted structures are a challenging test for electronic structure methods. Comparison of limited orbital space full CI calculations with CCSD(T) calculations within the same active spaces shows that post-CCSD(T) correlation contributions to relative energies are very minor. At the same time, relative energies are weakly sensitive to further basis set expansion, as proven by the minor energy differences between MP2/cc-pVDZ and explicitly correlated MP2-F12/cc-pVDZ-F12 calculations. Hence, our CCSD(T) reference values are reasonably well-converged in both 1-particle and n-particle spaces. While conventional MP2 and MP3 yield very poor results, SCS-MP2 and particularly SOS-MP2 and SCS-MP3 agree to better than 1 kcal mol-1 with the CCSD(T) relative energies. Regarding DFT methods, only M06-2X provides relative errors close to chemical accuracy with a RMSD of 1.2 kcal mol-1. While the original DSD-PBEP86 double hybrid performs fairly poorly for these extended p-systems, the errors drop down to 2 kcal mol-1 for the revised revDSD-PBEP86-NL, again showing that same-spin MP2-like correlation has a detrimental impact on performance like the SOS-MP2 results.

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Insights into Potent Therapeutical Antileukemic Agent L-glutaminase Enzyme Under Solid-state Fermentation: A Review

Current Drug Metabolism ◽

10.2174/1389200221666200421122147 ◽

2020 ◽

Vol 21 (3) ◽

pp. 211-220 ◽

Cited By ~ 1

Author(s):

Chandrasai Potla Durthi ◽

Madhuri Pola ◽

Satish Babu Rajulapati ◽

Anand Kishore Kola

Keyword(s):

Solid State ◽

Solid State Fermentation ◽

Food Industry ◽

Energy Requirement ◽

Production Studies ◽

Wide Range ◽

Hybridoma Technology ◽

Bacteria And Fungi ◽

The Stability ◽

Glutaminase Activity

Aim & objective: To review the applications and production studies of reported antileukemic drug L-glutaminase under Solid-state Fermentation (SSF). Overview: An amidohydrolase that gained economic importance because of its wide range of applications in the pharmaceutical industry, as well as the food industry, is L-glutaminase. The medical applications utilized it as an anti-tumor agent as well as an antiretroviral agent. L-glutaminase is employed in the food industry as an acrylamide degradation agent, as a flavor enhancer and for the synthesis of theanine. Another application includes its use in hybridoma technology as a biosensing agent. Because of its diverse applications, scientists are now focusing on enhancing the production and optimization of L-glutaminase from various sources by both Solid-state Fermentation (SSF) and submerged fermentation studies. Of both types of fermentation processes, SSF has gained importance because of its minimal cost and energy requirement. L-glutaminase can be produced by SSF from both bacteria and fungi. Single-factor studies, as well as multi-level optimization studies, were employed to enhance L-glutaminase production. It was concluded that L-glutaminase activity achieved by SSF was 1690 U/g using wheat bran and Bengal gram husk by applying feed-forward artificial neural network and genetic algorithm. The highest L-glutaminase activity achieved under SSF was 3300 U/gds from Bacillus sp., by mixture design. Purification and kinetics studies were also reported to find the molecular weight as well as the stability of L-glutaminase. Conclusion: The current review is focused on the production of L-glutaminase by SSF from both bacteria and fungi. It was concluded from reported literature that optimization studies enhanced L-glutaminase production. Researchers have also confirmed antileukemic and anti-tumor properties of the purified L-glutaminase on various cell lines.

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Enhanced Bilosomal Properties Resulted in Optimum Pharmacological Effects by Increased Acidification Pathways

Pharmaceutics ◽

10.3390/pharmaceutics13081184 ◽

2021 ◽

Vol 13 (8) ◽

pp. 1184

Author(s):

Armin Mooranian ◽

Thomas Foster ◽

Corina M Ionescu ◽

Daniel Walker ◽

Melissa Jones ◽

...

Keyword(s):

Bile Acids ◽

Biological Effects ◽

Cellular Respiration ◽

Full Potential ◽

Protective Effects ◽

Pharmacological Effects ◽

Β Cells ◽

Positive Effects ◽

Wide Range ◽

Anti Inflammatory

Introduction: Recent studies in our laboratory have shown that some bile acids, such as chenodeoxycholic acid (CDCA), can exert cellular protective effects when encapsulated with viable β-cells via anti-inflammatory and anti-oxidative stress mechanisms. However, to explore their full potential, formulating such bile acids (that are intrinsically lipophilic) can be challenging, particularly if larger doses are required for optimal pharmacological effects. One promising approach is the development of nano gels. Accordingly, this study aimed to examine biological effects of various concentrations of CDCA using various solubilising nano gel systems on encapsulated β-cells. Methods: Using our established cellular encapsulation system, the Ionic Gelation Vibrational Jet Flow technology, a wide range of CDCA β-cell capsules were produced and examined for morphological, biological, and inflammatory profiles. Results and Conclusion: Capsules’ morphology and topographic characteristics remained similar, regardless of CDCA or nano gel concentrations. The best pharmacological, anti-inflammatory, and cellular respiration, metabolism, and energy production effects were observed at high CDCA and nano gel concentrations, suggesting dose-dependent cellular protective and positive effects of CDCA when incorporated with high loading nano gel.

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Mineral Physicochemistry Underlying Feature-Based Extraction of Mineral Abundance and Composition from Shortwave, Mid and Thermal Infrared Reflectance Spectra

Minerals ◽

10.3390/min11040347 ◽

2021 ◽

Vol 11 (4) ◽

pp. 347

Author(s):

Carsten Laukamp ◽

Andrew Rodger ◽

Monica LeGras ◽

Heta Lampinen ◽

Ian C. Lau ◽

...

Keyword(s):

Mineral Exploration ◽

Relevant Information ◽

Ore Deposits ◽

Reflectance Spectra ◽

Full Potential ◽

Infrared Reflectance ◽

Vibrational Modes ◽

Diagnostic Features ◽

Wide Range ◽

Mineral Assemblages

Reflectance spectroscopy allows cost-effective and rapid mineral characterisation, addressing mineral exploration and mining challenges. Shortwave (SWIR), mid (MIR) and thermal (TIR) infrared reflectance spectra are collected in a wide range of environments and scales, with instrumentation ranging from spaceborne, airborne, field and drill core sensors to IR microscopy. However, interpretation of reflectance spectra is, due to the abundance of potential vibrational modes in mineral assemblages, non-trivial and requires a thorough understanding of the potential factors contributing to the reflectance spectra. In order to close the gap between understanding mineral-diagnostic absorption features and efficient interpretation of reflectance spectra, an up-to-date overview of major vibrational modes of rock-forming minerals in the SWIR, MIR and TIR is provided. A series of scripts are proposed that allow the extraction of the relative intensity or wavelength position of single absorption and other mineral-diagnostic features. Binary discrimination diagrams can assist in rapidly evaluating mineral assemblages, and relative abundance and chemical composition of key vector minerals, in hydrothermal ore deposits. The aim of this contribution is to make geologically relevant information more easily extractable from reflectance spectra, enabling the mineral resources and geoscience communities to realise the full potential of hyperspectral sensing technologies.

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Polymer-Drug Conjugates as Nanotheranostic Agents

Journal of Nanotheranostics ◽

10.3390/jnt2010005 ◽

2021 ◽

Vol 2 (1) ◽

pp. 63-81

Author(s):

Sajana Manandhar ◽

Erica Sjöholm ◽

Johan Bobacka ◽

Jessica M. Rosenholm ◽

Kuldeep K. Bansal

Keyword(s):

Drug Delivery ◽

Drug Release ◽

Treatment Options ◽

The Body ◽

Drug Conjugates ◽

Imaging Characteristics ◽

Wide Range ◽

Systemic Side Effects ◽

Theranostic Agents ◽

The Stability

Since the last decade, the polymer-drug conjugate (PDC) approach has emerged as one of the most promising drug-delivery technologies owing to several benefits like circumventing premature drug release, offering controlled and targeted drug delivery, improving the stability, safety, and kinetics of conjugated drugs, and so forth. In recent years, PDC technology has advanced with the objective to further enhance the treatment outcomes by integrating nanotechnology and multifunctional characteristics into these systems. One such development is the ability of PDCs to act as theranostic agents, permitting simultaneous diagnosis and treatment options. Theranostic nanocarriers offer the opportunity to track the distribution of PDCs within the body and help to localize the diseased site. This characteristic is of particular interest, especially among those therapeutic approaches where external stimuli are supposed to be applied for abrupt drug release at the target site for localized delivery to avoid systemic side effects (e.g., Visudyne®). Thus, with the help of this review article, we are presenting the most recent updates in the domain of PDCs as nanotheranostic agents. Different methodologies utilized to design PDCs along with imaging characteristics and their applicability in a wide range of diseases, have been summarized in this article.

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