Mohammed elamine Djeghlal - Academia.edu (original) (raw)

Papers by Mohammed elamine Djeghlal

Journal of Chemical Technology and Metallurgy, Jan 30, 2023

In thе present work, X80 WCrV 18-04-01 steel was borided using a powder method in an electric fur... more In thе present work, X80 WCrV 18-04-01 steel was borided using a powder method in an electric furnace at a temperature of 1223 K for 1, 2 and 8 h. The powder used is composed of 5 % B 4 C, 5 % NaBF 4 and 90 % SiC. The boride layers formed on the X80 WCrV 18-04-01 steel was characterized by the optical microscopy and X-ray Diffraction (XRD) analysis. A recent kinetic approach based on the integral method has been used to estimate the boron diffusion coefficients in the bilayer (FeB + Fe 2 B) formed on X80 WCrV 18-04-01 steel based on results from the literature. An equation was obtained, after solving the system of algebraic differential equations, to estimate the thickness of the bilayer (FeB + Fe 2 B) in order to compare it with the experimental thicknesses. A good agreement was obtained between the predicted and the experimental values. As a result, the activation energy for boron diffusion in X80 WCrV 18-04-01 steel was estimated 212.83 kJ mol-1. The validation of the model was extended by considering the boriding treatment at 1223 K for 1h and 8h, giving a good correlation with the experimental data.

Chinese Journal of Physics, Feb 1, 2020

Comparative study on Cu 2 ZnSn(S,Se) 4 based thin film solar cell performances by adding various ... more Comparative study on Cu 2 ZnSn(S,Se) 4 based thin film solar cell performances by adding various back surface field (BSF) layers,

Optik, Oct 1, 2020

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Optik, Sep 1, 2021

Abstract In this paper, a new CZTS/CZTSSe tandem solar cell design has been proposed to reach ult... more Abstract In this paper, a new CZTS/CZTSSe tandem solar cell design has been proposed to reach ultrahigh efficiency values at low fabrication cost. The proposed tandem design consists of a CZTS-based and CZTSSe-based for top and bottom cells respectively. By the use of the SCAPS-1D software, an investigation study involving the impact of subcells parameters such as thickness and doping concentration on the device performance is carried out. The best efficiency of 15.01% was obtained at a thickness of 203.10 and 300 nm for top and bottom cells respectively. Moreover, an effective method has been applied in the aim of boosting the efficiency, by adding a back surface field (BSF) layer in the CZTS top cell. The BSF layer helps to enhance optical behavior and reduces recombination losses, and consequently reducing the Voc deficit. We have found that the proposed design (with thinner top cell of 147.42 nm) improves the efficiency of the tandem cell from 15.01% to 19.250%. This makes the optimized CZTS / CZTSSe tandem solar cell a potential alternative to achieve a high-efficiency as well as a stable tandem solar cell designs.

The International Journal of Advanced Manufacturing Technology, Sep 10, 2021

The aim of this work is to study the metallurgical and mechanical properties of dissimilar assemb... more The aim of this work is to study the metallurgical and mechanical properties of dissimilar assemblies of 2024 T3 and 7075 T6 structural hardening aluminum alloy by TIG twine electrode arc welding process. It will include a weld performed according to optimized welding parameters followed by a study of the macroscopic and microscopic evolution of the dissimilar assembly (2024-7075) using optical and scanning electron microscopy (SEM); In addition, the phase compositions were analyzed with an energy dispersive spectrometer (EDS). Tensile and microhardness tests were performed. The tensile fracture was observed by SEM. We have found that this process thins the weld bead and reduces the size of the heat affected zone (HAZ) of the welded joint. The microhardness is lower in the melted area and higher on the side of the area affected by the heat especially for 7075 alloy, resulting in brittle strength and a sudden drop in breaking strength. 5. The maximum load of the 2024 T3-7075 T6 assembly is satisfactory since it can converge to the maximum load with the friction stir welding technique. Despite the brittle fracture.

Optik, Mar 1, 2019

In this research work, SCAPS-1D simulator is used to model and investigate the CZTS (Cu2ZnSnS4) s... more In this research work, SCAPS-1D simulator is used to model and investigate the CZTS (Cu2ZnSnS4) solar cells. A substrate cell structure ZnO/CdS/CZTS/Mo was used as a base model. A novel structure is proposed in which a back surface field (BSF) layer is efficiency of 14.11% under 1.5 AMG illuminations, which corresponding to following electrical parameters: Jsc = 24.57mA/cm 2 , Voc = 0.988Volt, and fill factor = 58.06%. Also, at the end, the effect of the BSF layer on the band diagram and the generation-recombination profiles of CZTS solar cell is discussed.

Journal of Nano-and electronic Physics, 2018

In this work, a simulation of the CZTSSe (Cu2ZnSn(S,Se)4) solar cell with Al/ZnO:Al/ZnO(i)/CdS/ C... more In this work, a simulation of the CZTSSe (Cu2ZnSn(S,Se)4) solar cell with Al/ZnO:Al/ZnO(i)/CdS/ CZTSSe/Mo structure have been studied using the SCAPS-1D (Solar Cell Capacitance Simulator in one Dimension). The simulation results have been validated with real experimental results. Next, a novel structure is proposed in which a back surface field (BSF) layer is inserted in order to boost the solar cell performance, a CZTSSe layer has been used as (BSF) layer. The efficiency of CZTSSe solar cell increases from 12.3 % to 15.3 % by inserting a BSF layer. Finally, an optimization of different physical parameters (Thickness and doping concentration) of BSF layer has been done, and the optimum values are determined. In this research work, the proposed structure of CZTSSe solar cells with optimum parameters showed higher functional properties, The maximum value of efficiency achieved was 16.98 % with Jsc  36.31 mA/cm 2 , Voc  0.69 V, and FF  69.60% under 1.5G AM illumination.

Springer proceedings in energy, 2020

In this work, a simulation of the CZTSSe solar cell with Al/ZnO: Al/ZnO(i)/CdS/CZTSSe/Mo structur... more In this work, a simulation of the CZTSSe solar cell with Al/ZnO: Al/ZnO(i)/CdS/CZTSSe/Mo structure have been studied using the SCAPS-1D (Solar Cell Capacitance Simulator in one Dimension). The simulation results have been validated with real experimental results. Next, a novel structure is proposed in which a CZTSe layer is stacked in the back side of the solar cell in order to boost its performances. The efficiency of CZTSSe solar cell increases from 12.3% to 15.3% by inserting the CZTSe layer. Finally, we carried out an optimization of different physical parameters (Thickness and doping concentration) of CZTSe stacked layer to determine the optimum values. The proposed structure of CZTSSe solar cells with optimum parameters showed higher functional properties. The maximum value of efficiency achieved was 16.77% with JSC = 36.81mA/cm2, VOC = 0.657V and FF = 69.19% under AM1.5G illumination at 10 nm thickness and 5E19 cm−3 doping concentration.

Applied Physics A, 2020

Due to their high thermal stability under severe working conditions and harsh environment, nickel... more Due to their high thermal stability under severe working conditions and harsh environment, nickel (Ni)-based superalloys, such as Inconel 718, Inconel 738, GTD11, and René 40, are largely used in gas turbine industry. The gamma prime (γʹ) precipitates, that are coherent with the gamma (γ) matrix in these superalloys, provide excellent mechanical properties at high operating temperatures. However, after a long time of functioning, (γʹ) precipitates coarsen and lose their coherency with the matrix, which causes damages in gas turbine blades. The main purpose of this paper is to study the effect of both solid solution and aging heat treatments temperatures on the microstructural evolution in an Inconel 738 superalloy blade, which was received after few tens of thousands of service hours. The resulting microstructures were analyzed by using scanning electron microscopy and optical microscopy along with Vickers microhardness measurements. The obtained results show that the Vickers microhardness of the studied superalloy is related to size, shape, volume fraction, and distribution of the hardening phase (γʹ) [Ni 3 (Al, Ti)], and to its carbides as well. It was found that the microstructural stability is related to the working temperature.

Materials Research Express, 2019

Annales de Chimie Science des Matériaux, 2003

Optik, 2020

In this paper, a comparative study on generation and recombination process in different CZTS desi... more In this paper, a comparative study on generation and recombination process in different CZTS designs has been carried out in which their performances and band alignment are invistigated. Firstly, CdS/CZTS design has been modeled using the SCAPS-1D. Secondely, new designs have been proposed in which a back surface field (BSF) layer is inserted and CdS layer is replaced by ZnS. The obtained results exhibit a boosted efficiency from 12.03 % to 14.14 % by inserting a BSF layer with a ZnS buffer layer. The analysis of generation and recombination reveals a high recombination in CdS/CZTS interface in comparaison with ZnS/CZTS due to the high density of defect states at the CdS/CZTS interface. BSF increases recombination in P-region. Whereas, it fairly impacts generation process. ZnS/CZTS/BSF design enhances the collection efficiency in short and long wave length regions resulting in higher solar cell performances (VOC =0.89 V, JSC =25.38mA/cm2, FF=62.44 %, η=14.14 %).

Journal of Nano- and Electronic Physics

Journal of Nano- and Electronic Physics, 2018

The International Journal of Advanced Manufacturing Technology

Chinese Journal of Physics