NIMP| Outman EL KHOUJA, Author at NIMP

Resume

Outman El KHOUJA, assistant researcher (since June 2021), born in 1994, graduated from the Faculty of Sciences Ain Chock -Specialization Energy Physics at Hassan II University Casablanca, Morocco, has a MSc degree in Materials engineering and characterization at Ibn Tofail University (UIT), Faculty of Science (FSK), Kenitra, Morocco. PhD student at Laboratory of Materials Physics and Subatomics, FSK, UIT since December 2019. Work experience: National Institute of Materials Physics (NIMP) (June 2021 – to date), International Center of Theoretical Physics (ICTP) grant (November 2020 to Jun 2021) at NIMP, chemistry and electrochemistry laboratory assistant (2019, 2020) – FSK, Kenitra, Morocco. Main areas of interest/ expertise: Preparation of semiconductor thin films by physical, chemical, and electrochemical methods (magnetron sputtering, electrodeposition, spray pyrolysis, Mist-CVD, Successive Ionic Layer Deposition (SILAR), and Chemical Bath Deposition (CBD)), materials characterization (X-ray diffraction (XRD), Conventional spectroscopies (UV-Vis, IR), SEM-EDS, Raman Spectroscopy, Electrochemistry). Publication (Last Updated November 2022): 8 articles published in Web of Science® (WoS) journals with impact factor (e.g. Ceram. Int., J. Alloy. Compd., Thin Solid Films), Hirsch index: 3, Citations (without self-citations): 15. Professional profile web-links: Brainmap https://brainmap.ro/outman-el-khouja; ORCID ID: 0000-0003-3471-0353; WoS ResearcherID: EUR-9887-2022

Publications

1. ZnS stacking order influence on the formation of Zn-poor and Zn-rich Cu2ZnSnS4 phase

Authors: Zaki, MY; El Khouja, O; Nouneh, K; Touhami, ME; Matei, E; Azmi, S; Rusu, MI; Grigorescu, CEA; Briche, S; Boutamart, M; Badica, P; Burdusel, M; Secu, M; Pintilie, L; Galca, AC

Published: MAY 2022, JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS, 33, DOI: 10.1007/s10854-022-08160-6

This paper reports the synthesis and characterization of Cu2ZnSnS4 (CZTS) absorber films, prepared by a two-step electrodeposition of a ZnS (zinc sulfide) binary and a CZT (copper, zinc and tin) ternary precursors on Mo/Ti/Si substrates. The as-electrodeposited ZnS/CZT and CZT/ZnS stacks were thermally treated in a tubular furnace in sulfur environment at 550 degrees C. The role of the ZnS buffer layer is to provide a zinc and sulfur reservoir, needed to complete the formation of kesterite phase. X-ray diffraction and Raman analyses revealed the formation of the CZTS phase. The surface morphology and chemical composition of the films were studied using a scanning electron microscope. The bandgap values inferred from diffuse reflectance data, are discussed with respect to the stoichiometry which is considerably affected by the order of the stacks. Room-temperature photoluminescence of the CZT/ZnS sample showed a board PL band of 1.51 eV. It was found that the film with a ZnS layer on top is preferred for the formation of a Zn-rich single CZTS phase.

2. ZnS stacking order influence on the formation of Zn-poor and Zn-rich Cu2ZnSnS4 phase

Authors: Zaki, MY; El Khouja, O; Nouneh, K; Touhami, ME; Matei, E; Azmi, S; Rusu, MI; Grigorescu, CEA; Briche, S; Boutamart, M; Badica, P; Burdusel, M; Secu, M; Pintilie, L; Galca, AC

Published: APR 2022, JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS, DOI: 10.1007/s10854-022-08160-6

3. Bulk and surface characteristics of co-electrodeposited Cu2FeSnS4 thin films sulfurized at different annealing temperatures

Authors: El Khouja, O; Negrila, CC; Nouneh, K; Secu, M; Touhami, ME; Matei, E; Stancu, V; Enculescu, M; Kuncser, V; Galca, AC

Published: JUN 15 2022, JOURNAL OF ALLOYS AND COMPOUNDS, 906, 164379, DOI: 10.1016/j.jallcom.2022.164379

In this study, stannite, Cu2FeSnS4 (CFTS), absorber films were obtained by electrodeposition on Molybdenum-coated soda-lime substrates, followed by sulfurization treatment at certain temperatures in the 400-550 degrees C range. The purposes of this work were to control the manufacturing of CFTS films with good stoichiometry, high crystallinity and to study the annealing temperature impact on CFTS films properties. The X-ray diffraction and the Raman spectroscopy measurement distinguished the CFTS phase formation, with a presence of SnS2 secondary phase. The energy dispersive spectroscopy results reveal compositional differences between samples as well as the in-depth gradients. The photoluminescence emission band around 1.35-1.40 eV is slightly below the direct bandgap inferred from the conventional spectroscopy (diffuse reflectance). X-ray photoelectron spectroscopy results indicate clearly a high amount of Sn on the surface. The Conversion Electron Mossbauer unveiled the presence of Fe in the chalcogenide unit cell. The electrochemical characteristics of the synthesized films are also given. (c) 2022 Elsevier B.V. All rights reserved.

4. Structural and transport properties of Cu2CoSnS4 films prepared by spray pyrolysis

Authors: El Khouja, O; Assahsahi, I; Nouneh, K; Touhami, ME; Secu, M; Talbi, A; Khaaissa, Y; Matei, E; Stancu, V; Galatanu, A; Galca, AC

Published: NOV 1 2022, CERAMICS INTERNATIONAL, 48, DOI: 10.1016/j.ceramint.2022.07.185

In the present work, stannite Cu2CoSnS4 (CCTS) films were elaborated using spray pyrolysis method on soda-lime glass, at different deposition temperatures (T-d = 250, 300, and 350 degrees C), followed by different chosen sulfurization temperatures (T-s = 450, 500, and 550 degrees C). X-ray diffraction (XRD) revealed the nearly single-phase formation of CCTS films at 300 degrees C deposition temperature. After sulfurization in argon flow, the XRD lines become narrower, the average crystallite size expanding above 70 nm. The Raman spectroscopy analysis confirmed the stannite structure formation, as well as the presence CoS2 secondary phases, which reduces at higher sulfurization temperature (550 degrees C). The energy dispersive spectroscopy results indicated atomic ratios of Cu/Co/Sn/S close to the ideal stoichiometric ratio 2:1:1:4. The room temperature photoluminescence emission is recorded with maximum in the 1.35-1.40 eV range. Thermoelectric properties are measured up to 130 degrees C, the films show poor power factor as a result of small positive Seebeck coefficients 10-45 Of K -1 and low electrical conductivity despite of having relatively high carrier concentration (similar to 10(20) cm(-3)).

5. New Chalcogenide Glass-Ceramics Based on Ge-Zn-Se for IR Applications

Authors: Velea, A; Sava, F; Badica, P; Burdusel, M; Mihai, C; Galca, AC; Matei, E; Buruiana, AT; El Khouja, O; Calvez, L

Published: JUL 2022, MATERIALS, 15, 5002, DOI: 10.3390/ma15145002

The consumer market requests infrared (IR) optical components, made of relatively abundant and environmentally friendly materials, to be integrated or attached to smartphones. For this purpose, three new chalcogenides samples, namely Ge23.3Zn30.0Se46.7 (d_GZSe-1), Ge26.7Zn20.0Se53.3 (d_GZSe-2) and Ba4.0Ge12.0Zn17.0Se59.0I8.0 (d_GZSe-3) were obtained by mechanical alloying and processed by spark plasma sintering into dense bulk disks. Obtaining a completely amorphous and homogeneous material proved to be difficult. d_GZSe-2 and d_GZSe-3 are glass-ceramics with the amount of the amorphous phase being 19.7 and 51.4 wt. %, while d_GZSe-1 is fully polycrystalline. Doping with barium and iodine preserves the amorphous phase formed by milling and lowers the sintering temperature from 350 degrees C to 200 degrees C. The main crystalline phase in all of the prepared samples is cubic ZnSe or cubic Zn0.5Ge0.25Se, while in d_GZSe-3 the amorphous phase contains GeSe4 clusters. The color of the first two sintered samples is black (the band gap values are 0.42 and 0.79 eV), while d_GZSe-3 is red (E-g is 1.37 eV) and is transparent in IR domain. These results are promising for future research in IR materials and thin films.

6. Structural, morphological and optical properties of Cu-Fe-Sn-S thin films prepared by electrodeposition at fixed applied potential

Authors: El Khouja, O; Galca, AC; Nouneh, K; Zaki, MY; Touhami, ME; Taibi, M; Matei, E; Negrila, CC; Enculescu, M; Pintilie, L

Published: MAR 1 2021, THIN SOLID FILMS, 721, DOI: 10.1016/j.tsf.2021.138547

Cu-Fe-Sn-S films were obtained on indium tin oxide / glass substrates by a low-cost electrodeposition using an aqueous solution of CuSO4, FeSO4, SnSO4, and Na2S2O3 at room temperature followed by high-temperature sulfurization (500 degrees C) in argon flow. A range of cathodic potentials have been used for electrodeposition, those being chosen after a preliminary cyclic voltammetry study. The coatings were characterized using X-ray diffraction, Raman spectroscopy, scanning electron microscopy, energy dispersive spectroscopy, X-ray Photoelectron Spectroscopy and conventional spectroscopy (diffuse reflectance and specular transmission). The results are discussed with respect to the used applied potential.

7. Experimental and numerical simulation of deposition time effect on ZnS thin films for CZTS-based solar cells

Authors: Khaaissa, Y; Talbi, A; Nouneh, K; El Khouja, O; Ahmoum, H; Galca, AC; Belahmar, A; Li, GJ; Wang, Q

Published: SEP 2021, OPTICAL AND QUANTUM ELECTRONICS, 53, DOI: 10.1007/s11082-021-03143-z

High-quality ZnS thin films as buffer layer have been successfully synthesized and simulated using the low-cost Mist CVD technique and the SCAPS-1D software for different deposition times (30, 40, 50, and 60 min). The structural, morphological, and optical properties of the prepared ZnS films have been investigated using X-ray diffraction (XRD), scanning electronic microscopy (SEM), atomic force microscopy (AFM), and UV-Vis spectrophotometer. The time deposition effect on ZnS films' efficiency as a buffer layer has been evaluated. XRD pattern confirms the hexagonal/cubic structure of the prepared samples, with (111) as preferred orientation. Raman spectra confirm XRD findings by the two peaks located at 348 cm(-1) and 697 cm(-1) which correspond to ZnS samples' cubic and hexagonal structures. Scanning electronic microscopy (SEM) and atomic force microscopy (AFM) images show densely uniform grains with precise shapes and boundaries covering the entire sample's surface with a relative roughness for all deposition times. The optical transmittance shows an average of 78% in the visual field of light with an optical band gap varying between 3.69 and 3.80 eV. Numerical simulation of ZnO:Al/ZnS/CZTS/Mo cell using SCAPS-1D software shows that the sample deposited for 30 min presents the best performance with an efficiency of up to 8.9%.

8. Secondary phases and their influence on optical and electrical properties of electrodeposited Cu2FeSnS4 films

Authors: El Khouja, O; Galca, AC; Zaki, MY; Talbi, A; Ahmoum, H; Nouneh, K; Touhami, ME; Taibi, M; Matei, E; Enculescu, M; Pintilie, L

Published: NOV 2021, APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING, 127, DOI: 10.1007/s00339-021-05038-y

Cu-Fe-Sn-S have been electrodeposited on indium tin oxide coated glass (ITO/glass) substrates, varying only the deposition time, followed by sulfurization in argon atmosphere at a temperature of 500 degrees C. X-ray diffraction patterns confirmed the formation of polycrystalline CFTS and other secondary phases. The Raman spectroscopy results confirm the formation of stannite phase, by the existence of the most intense peak at 330 cm(-1) corresponding to A-symmetry vibrational mode, while the SnS2 surface phase reduces upon increasing deposition time. The inferred bandgaps by specular transmission are in 1.4-1.7 eV range, influenced by the detected orthorhombic Cu4SnS4 and rhodostannite secondary phases. The electrical measurements confirm the p-type nature of the films, while density of free carriers is relatively high (similar to 10(19) cm(-3)), leading to extremely low resistivity in the Omega cm range.

Outman EL KHOUJA

Assistant Researcher