In this paper, for developing analytical and semi-analytical methods to evaluate band structure in photonic quasicrystals the perturbation theory is examined. It is shown that more isotropic and complete photonic band gap can be observed under low dielectric contrast for photonic quasicrystals in comparison with ordinary crystals and because of this feature of photonic quasicrystals, perturbati...

With the development of monochromators for transmission electron microscopes, valence electron energy-loss spectroscopy (VEELS) has become a powerful technique to study the band structure of materials with high spatial resolution. However, artefacts such as Cerenkov radiation and surface effects pose a limit for interpretation of the low-loss spectra; also the inelastic delocalisation restricts...

[email protected] Abstract – The CdO thin films were deposited using NaOH as the complexing agent by Successive Ionic Layer Adsorption and Reaction (SILAR) method. The UV-VIS-NIR spectroscopy was used for film characterization. The deposited CdO thin film shows high absorbance in the UV region and low in the visible to near IR region of the spectroscopy. The energy band gap of the deposi...

The research in the organic π-conjugated molecules and polymers based on thiophenehas become one of the most interesting topics in the field of chemistry physics and materials science. These compounds have become the most promising materials for the optoelectronic device technology.. The use of low band gap materials is a viable method for better harvesting of the solar spectrum and increasing ...

the structure and the electronic properties of single-walled zigzag bn and b3c2n3 nanotubes (n, 0; n=4–10) were investigated using first-principles calculations based on a density functional theory. a plane–wave basis set with periodic boundary conditions in conjunction with vanderbilt ultrasoft pseudo-potential was employed. the energy gap of zb3c2n3nts was calculated and compared with the cor...

The research in the short-chain organic -conjugated molecules has become one of the most interesting topics in the fields of chemistry. These compounds have become the most promising materials for the optoelectronic device technology. The use of low band gap materials is a viable method for better harvesting of the solar spectrum and increasing its efficiency. The control of the band gap of th...

We report calculations of the electronic structure of silicene and the stability of its weakly buckled honeycomb lattice in an external electric field oriented perpendicular to the monolayer of Si atoms. The electric field produces a tunable band gap in the Dirac-type electronic spectrum, the gap being suppressed by a factor of about eight by the high polarizability of the system. At low electr...

The promising photovoltaic activity of pyrite (FeS2) is attributed to its excellent optical absorptivity and earth abundance, but its band gap, 0.95 eV, is slightly lower than the optimum value of 1.3 eV. Here we report the first investigation of strained FeS2, whose band gap can be increased by ∼0.3 eV. The influence of uniaxial and biaxial strains on the atomic structure as well as the electr...