نتایج جستجو برای: band gap diagram
تعداد نتایج: 321192 فیلتر نتایج به سال:
zno nanostructures have been synthesized by a simple reflux method, using different ionic liquids, such as 1-benzyl-3-methylimidazolium bromide ([bzmim][br]), 1,1'-(1,4 phenylenebis (methylene)) bis (3-methyl-1h-imidazol-3-ium) bromide ([mm-1,4-dbzim2][br]2) and 1-phenacyl-3-methylimidazolium bromide ([pmim][br]), with different amount of sodium hydroxide in water. also the effect of reaction t...
cumn2o4 nanoparticles, a semiconducting materials with tunable functionalities in solid oxide fuel cell, was successfully synthesized via a sol-gel method using its respective metal cations sources i.e. cu2+ and mn2+ in an appropriate complexing agent.the vibrational frequencies below 1000 cm-1 of the obtained materials confirmed the formation of metal-oxygen (m-o:cu-o, mn-o) bond in the sample...
We investigate the photonic properties of one dimensional photonic crystals realized on Silicon On Insulator channel slot-waveguide to engineer slow light effects. Various geometries of the photonic pattern have been characterized and their photonic band-gap structure analyzed. The optimal geometry has been further used to realize a coupled resonator optical waveguide (CROW). A first optimizati...
The photoluminescence (PL) and PL excitation (PLE) spectra of the isolated Zn vacancy sVZnd in ZnSe are measured under hydrostatic pressure to 50 kbar at 7 K. The PL band shifts with pressure, roughly 30% faster than the band gap. Compression decreases the Stokes shift, reflecting a reduction in the C3y lattice relaxation around the V 2 Zn site. Defect-molecule calculations show that this arise...
A photonic crystal-based TE to TM polarization converter for integrated optical communication is proposed in this paper. The photonic crystal consists of air circular-holes in slab waveguide. The radius of holes are determined to be 291nm having lattice constant of 640nm using the gap map and band diagram. The polarization converter is composed of an InGaAsP triangular-shaped waveguide on SiO2 ...
In this letter, titania nanopowder and titania-silica nanocomposite were prepared using sol-gel method. Although the size of nanocrystallites and the mass fraction percent age of rutile phase ( after phase transformation ) were increased by increasing calcination in the two samples , their size in titania-silica nanocomposite was smaller than that in pure titania . Moreover, the calculations ...
the purpose of this paper is the generalization of structure factor for rods by polygon section in two dimensional phononic crystals. if we use the plane wave expansion method (pwe) for the propagation of acoustic waves in 2d phononic crystals, structure factor will be an important quantity. in order to confirm the obtained relations, we have calculated the band structure for xy and z vibration...
zno nanorod was prepared by microwave assisted method. the crystal structure of the nano powders were confirmed by x-ray diffraction analysis and the mean particle size was estimated by the scherrer,s formula .the surface morphology of the nano particles were analyzed by using sem . the absorption spectrum of the material in the uv-vis range was recorded .the energy band gap of the material w...
We study a generalisation of the Hatano-Nelson Hamiltonian in which a periodic modulation of the site energies is present in addition to the usual random distribution. The system can then become localized by disorder or develop a band gap, and the eigenspectrum shows a wide variety of topologies. We determine the phase diagram, and perform a finite size scaling analysis of the localization tran...
On the basis of a general symmetry analysis, this paper presents an empirical tight-binding (TB) model for the reference Pm-3m perovskite cubic phase of halide perovskites of general formula ABX3. The TB electronic band diagram, with and without spin orbit coupling effect of MAPbI3 has been determined based on state of the art density functional theory results including many body corrections (D...
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