Cu(In,Ga)Se₂ thin films (CIGS) on metallic substrate (titanium, molybdenum, aluminum, stainless steel) were prepared by a two-step selenization of Co-evaporated metallic precursors in Se-containing environment under N₂ gas flow. Structural properties of prepared thin film were studied. To characterize the optical quality and intrinsic defect nature low-temperature photoluminescence, were performed. Results shows that the structural and optical properties of Cu(In,Ga)Se₂ thin films strongly depend on the growth condition, charactristics of substrate and chemical composition. In2S3 thin layer has been used as buffer layer in CIGS solar cells and physical properties of them investigated. Solar cells were completed by vacuum deposition of ZnO/ZnO:Al layers and Ni/Al contact fingers. The surface morphology and bulk composition of thin films were investigated by scanning electron microscopy (SEM) equipped with energy-dispersive X-ray spectroscopy (EDS). The optical testing was carried out by recording transmittance spectra of the samples by spectrophotometers in the spectral range 190–3000 nm at a resolution of 1 nm. The better conversion efficiencies were around 12.0 %. 
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Cu2ZnSnS4 (CZTS) thin films were prepared by directly sputtering
Cu (In,Ga)Se2 quaternary target consisting of (Cu: 25%, Zn: 12.5%, Sn; 12.5%
and S: 50%). The composition and structure of CZTS layers have been
investigated after annealing at 200 0C, 350 0C and 500 0C under vacuum. The
results show that recrystallization of the CZTS thin film occurs and increasing
the grain size with a preferred orientation in the (112) direction was obtained. The
Raman spectra showed the existence of crystalline CZTS phase after annealing.
Optical transmission spectra were recorded within the range 300-900 nm. The
energy band gap (Eg) of the CZTS thin films was calculated before and after
annealing from the transmittance spectra using Beer-Lambert’s law. Results show
that Eg is dependent on the annealing temperature. The optical band gap of CZTS
also varied from 1.57 eV to 1.31 eV with increase in the annealing temperature
from 200 0C min to 500 0C. Manuscript profile

In this paper, a photonic crystal waveguide with point defects and lattice constant perturbations of +5%, -5% are being investigated. Firstly waveguide structures with constant and specific parameters are being studied and photonic band gap diagrams for TE/TM modes are depicted; then pulse propagation in the frequencies available in the band gap are shown. After that, effects of parameters like refractive indicesand radius of the rods on the band gap diagram of TE/TMmodes are evaluated. It has beenshown that, by increasing the refractive indices and radius of the rods, band gap diagrams would be shifted to lower frequency amounts.  Manuscript profile

Thin layer of titanium dioxide has been deposited on a glass sheet using RF magnetron sputtering under different preparation conditions. Phase, lattice parameters, optical features and morphology were investigated under different laboratory conditions in different thicknesses by using XRD, spectrophotometry and atomic force microscopic (AFM), within the visible spectrum range. Also, the lattice structure, in most cases, is tetragonal or a combination of tetragonal and orthorhombic. The band gap energy for each layer was measured using Tauc’s Plot. It was observed that the edge of absorption is reduced following an increase in thickness except for a thickness of 75 nm. By increasing the pressure, the band gap energy of the layers or the edge of absorption increases except for 0.04 mbar. By increasing the power, the band gap energy of the layers will change resulting in an increasing-decreasing trend in the edge of absorption, which can be the outcome of changes in the lattice formation. Nevertheless, it is obvious that the band gap energy, phase, lattice parameter and morphology is totally dependent on the laboratory conditions of making layers. Manuscript profile

We have studied the electron exchange-correlation effect on the
characteristics of the two-component unmagnetized dense quantum plasma with
streaming motion. For this purpose, we have used the quantum hydrodynamic model
(including the effects of a quantum statistical Fermi electron temperature) for studying
the propagation of an electrostatic electron plasma waves in such that plasma consisting
of quantum electrons and immobile ions. It is found that by regarding the latter effect, it
possible the excitation of two distinct modes. Some different cases such as:
unmagnetized, collisionless, classical cases and some formulas presented and discussed.
By using the reduced quantum hydrodynamic (QHD) model, the Korteweg de Vries
(KdV) equation incorporating the electron exchange-correlation effect is derived. It was
shown that the electron exchange-correlation phenomenon on the main quantities for both
rarefactive and compressive types of solitary-wave propagation can be important. In
particular, the arbitrary amplitude of electron solitary-wave experiences a spreading as
the effect of exchange-correlation becomes effective. Variations of the width of the
electron solitary wave for different plasma values were depicted. It was shown that by
increasing the exchange values, the width of soliton decrease. Manuscript profile

In this paper, graphene oxide (GO) and its functionalization with “Amio Methyl Phosphonic Acid” (AMPA) are synthesized using modified Hummers method. Crystal structure of the compounds is investigated by X-ray diffraction pattern (XRD). Fourier transform infrared spectroscopy (FTIR) clearly shows that the AMPA agent does really enter into the GO. Transmission electron microscope (TEM) images of the compounds reveal that they are in the form of nano-sheets. High resolution TEM (HRTEM) microscope is also used to observe and study the nanoscopic morphology of the structures. In addition, the samples are element-analyzed by energy dispersive X-ray spectroscope (EDS), and X-ray photoelectron spectroscopy (XPS) to get more information. Finally, the functionalization mechanism of GO with AMPA is studied and the mechanisms of “nucleophilic displacement” as well as “condensation reaction” are suggested andare experimentally confirmed. Due to the favorable properties of the synthesized material AMPA-GO, its use was suggested for water treatment and removal of heavy metals such as lead and strontium. Manuscript profile

In this work, we calculated the energy levels of truncated
pyramidal-shaped InAs/GaAs QDs by using the finite
element method by taking into account the ambient
temperature, because the system under study is not
symmetric, it is impossible to use the analytical method
to find the wave functions and energy levels of the
electron, and the finite element method is the solution to
such problems. We showed that, with increasing the
temperature, the energy level of both the ground state and
the first excited state as well as S-to-P transition
frequency increase. But the important point was that,
increasing the temperature can shift linear and nonlinear
susceptibility graphs to higher frequencies. For example,
for a pyramid with a base length of 25 nm and a height of
5 nm, at zero and 500 K the maximum linear and
nonlinear susceptibility values are shifted from 14
terahertz to the 18 terahertz. This ability can be effective
in designing optical devices. Manuscript profile

In this paper, we employed Raman spectroscopy to
investigate Indium sulfide thin layer films deposited on
glass substrates using the PVD method. The results showed
that the bandwidth and Raman shift of different In2S3 thin
films depended on the annealing temperature. In addition,
the crystallization stage from tetragonal to cubic occurred
at the excessive temperature range of 350-400 °C. The
Raman spectroscopy of the In2S3 thin films before
annealing and at 300 °C indicated the existence of β- In2S3
at 70, 166 and 281 cm-1 in the active modes of the spectra.
New modes that were related to α-In2S3 appeared at 126,
244, and 266 cm-1 after thermal treatment at 400 °C for 30
and 60 min. Our results are in agreement with the phase
transitions observed from the XRD analysis of In2S3 thin
films. There are few reports about the Raman spectroscopy
of In2S3 thin layer films deposited using vacuum thermal
evaporation. In the present paper, the Raman spectra of
In2S3 thin films with different thicknesses as well as the
effects of temperature on their depositions in vacuum were
examined. Manuscript profile

Abstract Plasmons in nanometer structures are caused by the interaction between electromagnetic waves and electrons on the metal surface. In this article, a comprehensive and detailed investigation of the effect of effective parameters on the performance of structured MIM waveguides (metal-insulator-metal) has been carried out. These structures are widely used in sensor applications based on refractive index changes or filters. This paper examines the impacts of altering factors like waveguide size, metal type, and insulation while also proposing novel structures with circular and square resonators,Then we simulated the structure of the MIM waveguide connected to the cavity of the T-shaped resonator for different values for the length L of the cavity, It is possible that this issue has a good use in filters and systems with high bandwidth to separate channels  . Also,the properties of surface plasmon polaritons emission were investigated in the case where a resonator is vertically connected to it. The transmission diagram had compared to the MIM waveguide without resonator. Manuscript profile

A novel absorber based on a one-dimensional photonic
crystal (PhC) is proposed by combining the absorption
property of gold and graphene films. We designed two
photonic crystals consisting of silicon and silicon
dioxide layers with lattice constants 125 and 260 that
alternate in one dimension. We placed a 125-nanometerthick
layer of graphene between the two photonic
crystals and an 8-nanometer-thick layer of gold at the
end of the second photonic crystal. When graphene is
placed between two photonic crystals, a topological edge
mode excitation creates a strong absorption
enhancement. In this study, the absorbing spectrums and
field distribution are analyzed by using the transfer
matrix and the 2.5 dimensional variational finite
difference time domain method (2.5 var.FDTD). The
absorption spectrum for different angles was studied
(θ=0 to 60), and more than 87 percent absorption can be
maintained for θ =40°. The results of our studies will
enhance the interaction between light and matter. Thus,
opening up the possibility of their application for the
absorption and modulation of light Manuscript profile