نتایج جستجو برای: go optical band gap

تعداد نتایج: 586818  

2014
P. S. Miedema M. Beye R. Könnecke G. Schiwietz A. Föhlisch

The band gap of semiconductors like silicon and silicon carbide (SiC) is the key for their device properties. In this research, the band gap of 6H-SiC and its temperature dependence were analyzed with silicon 2p x-ray absorption spectroscopy (XAS), x-ray emission spectroscopy (XES) and resonant inelastic x-ray scattering (RIXS) allowing for a separate analysis of the conduction-band minimum (CB...

La3+ and Sm3+ - doped Bi2Mn2O7 nanocatalysts were synthesized in 1 M NaOH aqueous solution, via a stoichiometric 1:1 Bi:Mn molar ratio hydrothermal method at 180 °C for 48 h. Bi(NO3)3, MnO2, La(NO3)3 and Sm2O3 were used as raw materials. The synthesized nanomaterials were characterized by powder X-ray diffraction (PXRD) technique. Both of the La3+ and Sm3+ - doped Bi2Mn2O7 nanomaterials were cr...

Parvan, , Esmaeili Ghodsi, , Mazloom, , Safari, ,

In this research, Zn0.97Cu0.03O nanoparticles are prepared by sol-gel method using various stabilizers (Mono, Di, and Tri-ethanolamine). The effect of stabilizers on the structural, morphological and optical properties of the nanoparticles were investigated. Study of X-ray diffraction pattern shows the hexagonal wurtzite structure of samples. The crystallite size, strain, stress, and deformatio...

2013
Zachary M Gibbs Aaron LaLonde G Jeffrey Snyder

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...

صالحی, حمدا…,

 The electronic structure and optical properties in tetragonal ceramics PbTiO3 are studied by using full-potential linearized augmented plane wave (FP-LAPW) method in density functional theory (DFT) with the generalized gradient approximation (GGA) by WIEN2K package. The theoretical calculated optical properties and energy loss (EEL) spectrum yield a static refractive index of 2.59 and a plasmo...

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...

Esmat Rafiee Farzin Emami

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...

1998
James R. CHELIKOWSKY Steven G. LOUIE

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...

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