Optical absorption edge measurements are performed on I doped PbTe using diffuse reflectance infrared Fourier transform spectroscopy. The Burstein–Moss shift, an increase in the absorption edge (optical band gap) with increasing doping level, is explored. The optical gap increases on the order of 0.1 eV for doping levels ranging from 3× 1018 to 2× 1020 cm−3, relevant doping levels for good ther...

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...

NiMn2O4 nanoparticles have been successfully prepared through sol-gel method. The effects of different factors such as the type of solvent, and amino acid temperature were investigated on the size and morphologies of products. The smallest particle size of NiMn2O4 nanoparticles was found to be 25 nm in diameter. The magnetic properties of the samples were also measured by an alternating gradien...

In this paper a new optical channel drop filter (CDF) based on two dimensional (2-D) photonic crystals (PhC) with hexagonal shaped structure is proposed and numerically demonstrated by using the finite-difference-time-domain (FDTD) and plane-wave-expansion (PWE) techniques. Photonic crystals (PhCs) are artificial dielectric nanostructure materials in which a periodic modulation of the material ...

Optical modeling was applied for obtaining absorbance spectra and band gap values for different morphology of ZnO semiconductor. In optical modeling, the relative permittivity scalars of zinc oxide coral like nanorods were calculated using the Bruggeman homogenization formalism. ZnO nano rods (ZONRs) as a nucleus layer were fabricated on the Indium Tin Oxide (ITO) by chronoamperometry (CA) in a...

Semiconductor structures with reduced dimensionality often have optical properties that are quite different than the optical properties of crystalline matter. For example, silicon has a band gap of about 1.2 eV in the crystalline state whereas nanocrystalline dots of silicon have “band gaps” of ∼ 2 eV or larger. Until recently, the modification of the gap from quantum confinement has not been e...

We demonstrate that a Bose-Einstein condensate in an optical lattice forms a reconfigurable matter-wave structure with a band-gap spectrum, which resembles a nonlinear photonic crystal for light waves. We study in detail the case of a two-dimensional square optical lattice and show that this atomic band-gap structure allows nonlinear localization of atomic Bloch waves in the form of two-dimensi...

This paper deals with the design and simulation of all-optical 4×2 encoderusing the wave interference effect in photonic crystals. By producing 4 opticalwaveguides as input and two waveguides as output, the given structure was designed.The size of the designed structure is 133.9 μm2. The given all-optical encoder has acontrast ratio of 13.2 dB, the response time of 0.45 ...