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Abstract In this work, we theoretically investigate the structural dependence of intersubband absorption of InGaAsSb/GaAs single quantum well structures. We begin by analyzing the impact of In and Sb incorporation on the critical thickness, conduction band offset and band gap energy. The first two electron energy levels E 12 and the corresponding wavelength were made for the In x Ga 1− x As 1- y Sb y /GaAs system and are analyzed in detail by solving the Schrödinger equation. Also, we have investigated effects of composition and well width on the intersubband absorption. In addition, the wavelength and absorption coefficient of the ISBT can be adjusted and optimized by changing the composition and the width of the SQW. Finally, strain effects on intersubband absorption and on the peak response wavelength have also been systematically studied. Our study shows that InGaAsSb/GaAs SQW will play a key role in research of electronics and photonic devices in the future. Highlights • Studied the effects of structural parameters on the Intersubband transition of InGaAsSb/GaAs QWs. • Absorption coefficient dependency on the InGaAsSb structural parameters has been investigated. • The effects of these parameters are numerically studied. • Effect of the strain on peak wavelength and on the maximum absorption has been verified. • InGaAsSb/GaAs is a good candidate as a novel material system for optoelectronic intersubband devices. [ABSTRACT FROM AUTHOR]

In this work we report a modeling and optimization of a novel core (p-GaN)-multishell (i-In x Ga 1-x N/i-GaN/n-Al 0.1 Ga 0.9 N/n-GaN) coaxial NWs with a total length of about 3 μm and a radius of 0.19 μm. The variation of Indium composition in the i-In x Ga 1-x N active layer shows that x = 15% is the optimal composition that gives a good short circuit current and efficiency of about 2.24 mA/cm 2 and 2.93%, respectively. Beyond x = 35% the structure starts to present deteriorations. Moreover, the optimal x composition founded provides a gain of about 12.9% of EQE in the mid-infrared part. The study of the variation of the total current density along the nanowire demonstrates that the maximum of this latter is located in AlGaN cladding shell layer and at the interfaces between the i-region and AlGaN cladding shell layer. In other hand, our results show that our structure presents an optimal efficiency of about 3.5% at a temperature of 275 K with the same AM1.5G solar spectrum. [ABSTRACT FROM AUTHOR]

This work focuses on the modeling and optimization of a structure based on InGaP/InGaAs/InGaAsN/Ge for photovoltaic. In this study we took into consideration the concentration effect of alloys x (In) and y (N) on the strain, the bandgap, the absorption and structure efficiency. It has been shown that the concentration of indium varies the strain and the bandgap. These two parameters change considerably the yield. Also it optimized the effect of alloys on the total absorption of the structure. For a concentration of indium x = 0.40 and y = 0.03 we had a absorption coefficient which is equal to 2 × 10 6 cm −1 . We have found 50% efficiency for the multi-junction structure based on In 0.55 Ga 0.45 P/In 0.40 Ga 0.60 As/In 0.30 Ga 0.70 As 0.97 N 0.03 /Ge. To achieve a reliable high efficiency multi-junction structure, we just need to optimize the concentrations of different alloys. [ABSTRACT FROM AUTHOR]

This paper deals with theoretical investigation of the performance of current and lattice matched GaN x As y P 1−x−y /Si double-junction solar cells. The nitrogen and arsenic concentrations ensuring lattice matching to Si are determined. The band gap of GaNAsP is calculated using the band anti-crossing model. Calculations were performed under 1-sun AM1.5 using the one diode ideal model. Impact of minor carrier lifetime and surface recombination in the top sub-cell on the cell performances is analyzed. Optimum compositions of the top sub-cell have been identified (x = 4.5%, y = 11.5% and E g = 1.68 eV). The simulation results predict, for the optimized GaNAsP/Si double-junction solar cell, a short circuit current J sc = 20 mA/cm 2 , an open circuit voltage V oc = 1.95 V, and a conversion efficiency η = 37.5%. [ABSTRACT FROM AUTHOR]

This work reports on theoretical studies on the GaInNAs material properties (bandgap, lattice mismatch, absorption coefficient) as grown on GaAs substrate. The Band Anti-Crossing (BAC) k ⋅ p 8 × 8 model has been used to determine the influence of indium and nitrogen concentrations on the position of conduction and valence bands. The incorporation of nitrogen at a level lower than 5% causes the split of the conduction band. For indium and nitrogen concentrations of 38% and 3.5%, respectively, the strained bandgap energy is 0.70 eV and the absorption coefficient of indium and nitrogen-rich compounds increases significantly. [ABSTRACT FROM AUTHOR]

In this paper, we present a splitting scheme for the pseudo-spectral numerical method namely the Split-Step Fourier method (SSFM), in our approach we expand the exponential term in a manner that a succession of linear and nonlinear terms are distributed uniformly along one step size, the splitting will be performed symmetrically, this new scheme will be tested on one of the most used nonlinear partial deferential equation in optics, namely the cubic quintic complex Ginzburg–Landau (CQCGL) equation, in this work we demonstrate that the accuracy of the Split Step Fourier method scheme can be improved by expanding and distributing it in small parts within one step. [ABSTRACT FROM AUTHOR]

In this paper we present the optimization of photoswitches constituted of a coplanar line introducing interdigitated MSM photodetectors in the central strip. The reflection and the transmission coefficients are studied with the aim of highlighting the influence of different geometrical parameters on the photoswitch microwave behavior. In pursuance of improving the performances, new topologies of coplanar lines introducing tapers of linear shapes, as well as tightening of ground planes around the central strip are proposed and studied. The outcomes showed that it is possible to achieve high insulation (-52.3dB) at the Off state. As for as the On/Off ratio is concerned, a value of 48.8dB is reached. [ABSTRACT FROM AUTHOR]

• A detailed phenolic composition (30 compounds) of P.lentiscus fruits is provided. • 9 anthocyanins were quantified and tentatively identified by LC–MS and RMN. • The phenolic profile varies greatly during the maturation of the fruit. • P. lentiscus at maturity is rich in delphidin derivatives and in gallocatechin. Pistacia lentiscus L. is a shrub of the Anacardiaceae family whose fruits are used in Tunisian and Algerian diets. The phenolic composition at 5 different physiological stages of the fruit was investigated using two different targeted methodologies: ultra-high-performance liquid chromatography–UV/visible detection (UHPLC-UV/vis) for anthocyanins and UHPLC coupled with tandem mass spectrometry (UHPLC-MS/MS) for the other polyphenols. For the specific analysis of anthocyanins, compound identification was confirmed by UHPLC-MS/MS and LC-NMR analysis. This study revealed the identification of 30 phenolic compounds including 9 anthocyanins, 7 flavanols, 7 flavonols, 2 phenolic acids, 1 stilbene, 2 flavanones, 1 flavanonol and 1 dihydrochalcone. Quantification showed significant qualitative and quantitative variation in phenolic content during the ripening of P. lentiscus fruits, flavonols being the main compounds for the unripe berries and anthocyanins for ripe berries. To the best of our knowledge, our study reports the presence of piceid and protocatechuic acid in P. lentiscus L. fruits, as well as several anthocyanins in Pistacia , for the first time. The results indicate potential applications of P. lentiscus L. fruits as a source of phenolic compounds to be used as nutraceuticals and as food colorants. [ABSTRACT FROM AUTHOR]

This paper focuses on the simulation and optimization of electrical and structural properties of high efficiency InGaP/InGaAs/Ge triple junction solar cells that incorporate In 0.7 Ga 0.3 As quantum dots with in the GaAs middle cell material. Current density-voltage (J-V) , external quantum efficiency (EQE) and capacitance-voltage (C-V) characteristics have been simulated and discussed. Results show that 30 pairs of In 0.70 Ga 0.30 As (QD)/GaAs (barrier) in the middle cell provide a relative enhancement of 13% in EQE in the 900–1000 nm wavelength range. This leads to a short-circuit current of 20 mA/cm2, an open circuit voltage of 2.3 V, a fill factor of 81.73%, and a conversion efficiency of 39.03%. The C-V revealed that a relatively high number of interfacial states are present in the 3-J cell structure including the QD layers, which decreases the open circuit voltage. In this study we benefited 18% of relative efficiency. • This paper focuses on the simulation and optimization of electrical and structural properties. • InGaP/GaAs/Ge triple junction (3-J) solar cell incorporated by variable number of In 0.7 Ge 0.3 As. • In this goal, current density-voltage, external quantum efficiency and the capacitance-voltage. • This leads to a short-circuit current of 19.97 mA/cm2, V OC = 2.3 V, FF = 81.73%, η = 39.03%. • The C-V revealed that a relatively high number can be present in the 3-J included the QD layers. [ABSTRACT FROM AUTHOR]

This paper describes a numerical study of ultrathin CIGS solar cell using the one-dimensional simulation program. The various properties of the absorber layer such as the band gap energy, the absorption coefficient, and the reflection coefficient are investigated. In addition, the impact of adding silicon to reduce the thickness of CIGS is also examined. We have carried out a theoretical study to show the influence of the thickness and the gallium concentration of the CIGS absorber layer on the performance of the Mo/Si/CIGS/ZnS/ZnO structure. It has been demonstrated that increasing x Ga and d CIGS affect the conversion efficiency, FF, V oc, and J sc. Finally, we have achieved a conversion efficiency η = 21.08% with an optimal value of gallium content equal to 20%when the thickness of the absorber layer has been reduced to 0.75 μm. This study allowed us to improve the performance of thin film solar cell. • The impact of material properties on solar cell performance. • The effect of Ga content and CIGS thickness on the conversion efficiency. • Ultrathin CIGS solar cell performance when adding a silicon layer. • The influence of defects and R s on the different electrical parameters. [ABSTRACT FROM AUTHOR]