Accurate prediction of band gap for new emerging materials is highly desirable the exploration potential applications. The gaps bulk and monolayer TMDs (MoS 2 , MoSe WS WSe ) are calculated with recently proposed by us GVJ‐2e method, which implemented within DFT framework without adjustable parameters based on total energies only. in very good agreement experimental ones both TMDs. For MoS direct predicted to be 1.88 eV, 1.57 2.03 1.67 eV correspondingly, TMDs, indirect 1.23 ), 1.09 (MoSe...

Abstract We have performed a theoretical study of the electronic band structure, density states, dielectric function and absorption coefficient isostructural BaSi 2 , BaGe SrGe compounds by means different ab initio methods. All materials are found to be indirect band‐gap semiconductors displaying almost equal dispersion bands close gap region. The energy gaps 0.83, 0.57 0.44 eV estimated for respectively. Analysis in comparison with data other semiconducting silicides indicates its...

In this part we present results of our ab initio calculations indicating that dispersion the bands near gap region for different phases WO3 (namely, ε-WO3, δ-WO3, γ-WO3, β-WO3, orth-WO3, α-WO3, and hex-WO3) is rather close. The rapid increase in absorption coefficient starts at lower energy range α-WO3 hex-WO3 than other accordance with calculated band gaps. An oxygen vacancy has turned out to decrease by 0.50 eV shift room temperature γ-WO3 phase. We have also traced changes caused...

The structural, electronic, and optical properties of II--IV--V${}_{2}$ (II $=$ Be, Mg, Zn, Cd; IV Si, Ge, Sn; V P, As) chalcopyrite-type ternaries have been theoretically investigated from first principles. compounds demonstrate semiconducting behavior, with the direct-band gap ranging about 0.2 to 2.2 eV, except for Be-containing materials, which indicate an indirect gap. band gaps in II--IV--P${}_{2}$ are always larger than corresponding ones II--IV--As${}_{2}$. All characterized by...

In the first part [D. B. Migas et al., J. Appl. Phys. 108, 093713 (2010)] electronic and optical properties of different phases WO3 have been considered. this we present results our ab initio calculations which clearly show that all Magnéli tungsten oxides WOx (namely, W32O84, W3O8, W18O49, W17O47, W5O14, W20O58, W25O73) are characterized by metal-like properties. Their band structures display an energy gap in valence just below Fermi level. We discuss how addition (removal) oxygen atoms to...

By means of first principles calculations, we have investigated the band structures different phases higher manganese silicides ($\mathrm{Mn}{\mathrm{Si}}_{x}$ with $x$ ranging from 1.73 to 1.75). In this family, ${\mathrm{Mn}}_{11}{\mathrm{Si}}_{19}$, ${\mathrm{Mn}}_{15}{\mathrm{Si}}_{26}$, and ${\mathrm{Mn}}_{27}{\mathrm{Si}}_{47}$ been found behave like degenerate semiconductors and, at same time, metals because Fermi level stays partly in energy gap valence close its top. The...

Band structure calculations for β-FeSi2 have been performed by the linear muffin-tin orbital method within local density approximation scheme including exchange and correlation effects. A detailed analysis of conduction valence band around high-symmetry points has shown existence a quasidirect gap in material. It is experimentally confirmed that between threshold energy optical interband transition 0.73 eV first direct with appreciable oscillator strength at about 0.87 there region which low...

Resistive switching materials are promising candidates for nonvolatile data storage and reconfiguration of electronic applications. Intensive studies have been carried out on sandwiched metal-insulator-metal structures to achieve high density on-chip circuitry non-volatile memory storage. Here, we provide insight into the mechanisms that govern highly reproducible controlled resistive via a nanofilament by using an asymmetric metal-insulator-semiconductor structure. In-situ transmission...

In this work transvinylation reactions with vinyl acetate were carried out to synthesize esters of some dicarboxylic acids. The divinyl acids such as adipic, glutaric, succinic, phthalic, isophthalic and terephthalic synthesized. conducted using activating reagents. carboxylic activated by 2-chloro-4,6-dimethoxy-1,3,5-triazine. Using potassium tertbutylate a base, an intermediate was formed that easily transfers the group acetate. This leads formation esters. Based on results research,...

Erbium photoluminescence at room temperature and 77 K has been observed from porous silicon doped with erbium a spin-on silica gel film. incorporation into dioxide the surface of rapid thermal processing temperatures higher than 1223 were found to be necessary prerequisite for erbium-related luminescence in silicon. No diffusion monocrystalline films was observed. The depth-dependent concentration bulk determined by secondary-neutral- secondary-ion-mass spectrometry depth profiling....

Our theoretical findings demonstrate for the first time a possibility of band-gap engineering monolayer MoS2 crystals by oxygen and presence vacancies. Oxygen atoms are revealed to substitute sulfur ones, forming stable MoS2−xOx ternary compounds, or adsorb on top atoms. The substituting provides decrease band gap from 1.86 1.64 eV transforms material direct-gap an indirect-gap semiconductor. surface adsorbed up 0.98 depending their location tending metallic character electron energy bands...

We have developed a technology and for the first time, present here, fabrication of continuous two-dimensionally crystallized g-C3N4 layered thin films oriented in hexagonal lattice c-plane on glass monocrystalline silicon substrates using chemical vapor deposition from melamine source. Scanning electron microscopy X-ray diffraction studies revealed that such with smooth surface good crystalline quality as thick up to 1.2 μm can be formed at synthesis temperature 550–625 °C. They are...

We report ab initio results for the ground-state properties, band diagrams, density of states, and dielectric functions ${\mathrm{Ca}}_{2}Z$ $(Z=\mathrm{Si},$ Ge, Sn, Pb) both in orthorhombic cubic structures. The calculations are performed by means total energy ultrasoft pseudopotential full potential linearized augmented plane wave methods within local generalized gradient approximations. estimated difference cohesion shows structure to be stable phase. also demonstrate that these...

We study the influence of multiple oxygen vacancy traps in percolated dielectric on postbreakdown random telegraph noise (RTN) digital fluctuations HfO2-based metal-oxide-semiconductor transistors. Our electrical characterization results indicate that these are triggered only beyond a certain gate stress voltage. First-principles calculations suggest vacancies to be responsible for formation subband forbidden band gap region, which affects triggering voltage (VTRIG) RTN and leads shrinkage HfO2 gap.

Passivation of barium disilicide ($\mathrm{BaS}{\mathrm{i}}_{2}$) films is very important for their use in solar cell applications. In this paper, we demonstrated the effect hydrogen (H) passivation on both photoresponsivity and minority-carrier lifetime $\mathrm{BaS}{\mathrm{i}}_{2}$ epitaxial grown by molecular beam epitaxy. First, examined growth conditions a 3-nm-thick hydrogenated amorphous silicon (a-Si) capping layer formed 500-nm-thick film found that an H supply duration...

Abstract A detailed study of structural, electronic and optical properties II–IV–N 2 ternary compounds (II = Be, Zn; IV Si, Ge) has been performed by means ab initio density functional theory calculations. The germanium containing were found to be direct‐gap semiconductors with gaps 3.37 eV 1.67 for BeGeN ZnGeN , respectively, oscillator strength direct transition comparable GaN. Two other silicon are characterized indirect 5.19 (3.32) BeSiN (ZnSiN ). Crystal structure being orthorhombic...

By means of ab initio calculations, we show that SiGe and Si-Ge core-shell nanowires with the ⟨001⟩ orientation having a diameter $1.5\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$ display competitive indirect-direct character gap. We have also investigated effects uniaxial strain along wire axis on dispersion bands close to gap possibility stabilize direct band Estimates dipole matrix elements first transition clearly indicate appreciable oscillator strength for Ge-core/Si-shell dimers {001}...