Browsing by Author "Messei, N"

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    ANNEALING EFFECT ON THE PROPERTIES OF INDIUM TIN OXIDES (IN2O3 :SN) THIN FILMS PREPARED BY ULTRASONIC SPRAY TECHNIC
    (university of el oued/جامعة الوادي, 2018-09-01) Hamani, N; Attaf, A; Saidi, H; Temmam, K. G.; Bouhdjer, A; Bennaceur, K; Messei, N; Benkhatta, Y.
    Indium tin oxide (ITO) films were deposited on glass substrates using ultrasonic spray technic. The ITO films (with 4% Sn-doping concentration at substrate temperature 400°C) were annealed in the air at 450, 500, and 550 °C for 2 h. The structural, morphological, electrical and optical properties of ITO films were investigated using: XRD, SEM, four-point probe and UV–visible. The XRD analysis reveals that the films are polycrystalline with body-centered cubic structure, and the cristaline state of the films improve with the increase of annealing temperature. Surface morphology of the films changes with the change of the annealing temperature. The high optical transmittance observed in the films annealed at 500 °C. The films annealed at 550°C shows the low electrical resistivity 25 10-4 Ωcm due to the decrease of the odsorbed oxygen on the surface morphology of this films.
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    INFLUENCE OF ABSORBER LAYER GRADUAL GAP PROFILE ON Cu2ZnSn(S1-Y SeY )4 SOLAR CELL EFFICIENCY: NUMERICAL STUDY
    (university of el oued/جامعة الوادي, 2021-01-01) Messei, N
    The gradual substitution of sulfur atoms (S) by selenium atoms (Se) in Cu2ZnSn(S1-y Sey )4 compounds causes a linear increase in the optical band-gap. For this reason, those compounds are suitable to implement band-gap engineering in compositionally graded solar cells. In this paper, we have worked to take advantage of this feature to enhance the performances of the basic uniform Kesterite and Stannite CZTS1–ySey solar cells. The influence of Tow grading profile was investigated: fully graded (a) and double graded (b). Fully graded Cell showed better parameters than compositionally uniform cells. In Double graded cells it appeared that front grading had a disruptive effect on solar cell parameters. In contrary back grading ameliorates significantly all cell parameters. As a result, the efficiency of kesterite and stannite cells was enhanced from 9.05 and 5.22% to 16.65 and 15.77 % respectively