Browsing by Author "Moualkia, H."

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    Investigation on chemical bath deposited CdS thin films
    (Oum-El-Bouaghi University, 2011) Moualkia, H.; Attaf, N.; Hadjeris, L.; Herissi, L.; Abdelmalek, N.
    n this work we report the structural, optical and electrical properties of CdS thin films prepared by chemical bath deposition (CBD) under the effect of solution temperatures. The XRD patterns show that the films have a hexagonal phase with a preferential (002) orientation. The structural parameters such as the grain size, dislocation density and strain are calculated for the films. The transmission spectra, recorded in the UV visible range reveal a high transmission coefficient (85%) in the obtained films. The optical gap values of 2-2, 4 eV are deduced from the UV-visible transmittance. The electrical characterizations show that the films deposited possess good optoelectronic properties.
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    Preparation and characterization of CdS thin films
    (IEEE, 2012) Moualkia, H.; Attaf, N.; Hadjeris, L.; Herissi, L.; Abdelmalek, N.
    In this work we report the structural, optical and electrical properties of CdS thin films prepared by chemical bath deposition (CBD) under the effect of solution temperatures. The solution temperatures used vary between 55 and 75 °C. The XRD patterns show that the films have a hexagonal phase with a preferential (002) orientation. The structural parameters such as the grain size, dislocation density and strain are calculated. The transmission spectra, recorded in the UV visible range, reveal a high transmission coefficient (85%) of the prepared films and an optical band gap values of 2 - 2.4 eV. The electrical measurements show that the dark conductivity values increase from 10-7 to 10-4 (Ω.cm)-1 at higher temperature (Ts > 65°C). It is found that the photoconductivity of the deposited films is two to five decades larger than the dark conductivity, and the photoconductivity to the dark conductivity ratio obtained at 3000 Lx vary from 102 to 105. From these results we inferred that the elaborated CdS thin films exhibit good properties intended for solar cell window layers.
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    Realization and study of ZnO thin films intended for optoelectronic applications
    (Oum-El-Bouaghi University, 2011) Herissi, L.; Hadjeris, L.; Moualkia, H.; Abdelmalek, N.; Hafdallah, A.; Attaf, N.; Aida, M. S.
    The objective of this study is the realization of zinc oxide (ZnO) thin films intended for optoelectronic applications. For this purpose, thin films were prepared by spray pyrolysis technique from zinc acetate solutions of different molarities (0.025 M, 0.05 M and 0.1 M) used as precursors on Si and glass substrates heated between 200 and 500 °C. The nozzle to substrate distance was varied between 20 and 30 cm. Structural, optical and electrical properties of the films have been studied. The results indicated that the films deposited were transparent in the visible region, well adherent to the substrates and presented surface roughness. All samples were polycrystalline in nature, having hexagonal würtzite type crystal structure. A (002) preferred orientation was observed at 450°C and a 0.025M molarity. The optical energy gap measured was about 3.3 eV. The refractive index values presented small variations with the deposition conditions and were located between 1.8 and 2.0. The electrical properties showed that the samples are natively n‑type semiconductor and the electrical conductivity at room temperature varied between 10-5 and 102 (Ω.cm)‑1.