High-frequency (optical) and low-frequency (static) dielectric constant versus band gap trends, as well as index of refraction versus band gap trends are plotted for 107 inorganic semiconductors and insulators. These plots are describable via power-law fitting. Dielectric screening trends that emerge from this analysis have important optical and electronic implications. For example, barrier low...

Water splitting for hydrogen production under sunlight using TiO2 as photo catalyst provides a better route for solar energy and attracts the attention of many researchers. The photo catalytic activity of TiO2 under sunlight irradiation depends on the band gap energy. The transition metal doped TiO2 shows an edge over TiO2 in optical absorbance and photo catalytic activity. Thin film of Cr dope...

In the present paper a novel structure for optical channel drop filter (CDF) based on photonic crystal ring resonator with circular core has been proposed. In order to design the proposed CDF, the plan wave expansion (PWE) method is applied for calculation of band structure and photonic band gap while the transmission characteristics of proposed CDF have been calculated using the finite differe...

   We have investigated the electronic and optical properties of AlN hexagonal nanosheets under different kinds of strains, using the band structure results obtained through the full potential linearized augmented plane wave method within the density functional theory. The results show that 10% uniaxial strain along the zig-zag direction induces an indirect to direct band-gap transition. Th...

Photonic band-gap (PBG) crystals offer new dimensions of freedom in controlling propagation of electromagnetic waves. The existence of stop-bands in the transmission characteristic of these crystals makes them a suitable element for the realization of many useful microwave and optical subsystems. In this paper, we calculate the propagation constant of a one-dimensional (1-D) photonic crystal by...

the effect of evaporation rate on structural, morphological and optical properties of electron beam evaporated cds thin films have been investigated. cds thin film deposited by electron beam evaporation method in 12nm/min and 60nm/min evaporation rates on glass substrates. x-ray diffraction, scanning electron microscopy, uv-vis-nir spectroscopy and atomic force microscopy were used to character...

Zinc Sulfide (ZnS) thin films were deposited on glass substrates at the pressure of 10-6 mbar by thermal resistor evaporation technique. The effects of annealing on the structural, optical properties of ZnS films were studied. Crystalline ZnS films have been analyzed by X-ray diffraction. Only cubic phase with the preferred (111) plane was found in ZnS films. Optical characteristics were studie...

in this article, zno and zno:mn nanoparticles prepared by reverse micelle method. the various crystalline properties of these nanoparticles such as size, d-spacing, strain, stress, dislocation density and texture coefficient have been calculated with the help of xrd spectrum. the xrd results indicated that the synthesized zno and zno:mn nanoparticles have a pure wurtzite (hexagonal phase) struc...

The optical band gap, extracted from absorption measurements, defines the figure of merit for transparent conducting oxides (TCOs). In many oxides, such as In O 2 3 or SnO2, inversion symmetry introduces a selection rule that blocks transitions from the valence-band maximum to the conduction-band minimum. This raises the absorption threshold and enlarges the optical gap relative to the fundamen...