College of Natural and Computational Sciences

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Subject: search.filters.subject.Chemical bath deposition

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    Studying The Effect Of Metallic Precursor Concentration On The Structural And Optical Properties Of Zinc sulfide Thin Films Synthesized By Chemical Bath Deposition Method
    (2024-05) Olchitu Bekele
    Zinc sulfide (ZnS) thin films with different concentrations of zinc chloride (0.3M, 0.5M, 0.7, 0.9M and 1.1M) have been deposited on a glass substrate made by chemical bath deposition technique in basic medium. Zinc chloride, thiourea, ammonia, and hydrazine hydrate were used to synthesize ZnS thin films. The films were annealed at 200°c. This study investigates how the concentration of metallic precursor affect the crystal structure and optical properties of Zinc sulfide thin films. The XRD result shows that no sharp peak which indicates the samples is amorphous nature. UV-Vis spectroscopy was used to analyze the optical characteristics of the deposited thin films. The absorbance increase with increasing of the zinc sulfide concentration and the band gap energy for the films prepared in different concentration of zinc chloride decrease from 3.53 to 3.42 eV with increasing of zinc sulfide concentrations. The results demonstrated that concentration of metallic precursor have distinct effects on optical absorbance and band gap energy.
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    INFLUENCE OF CATIONIC PRECURSOR CONCENTRATION ON THE OPTICAL AND STRUCTURAL PROPERTIES OF COPPER OXIDE THIN FILMS DEPOSITED BY CHEMICAL BATH DEPOSITION TECHNIQUE
    (HAWASSA UNIVERSITY, 2024-11) HUSSEN KELLI
    Copper oxide thin films were fabricated on glass substrates using the chemical bath deposition method with a deposition time of 20 minutes. The structural and optical properties of the films were investigated using X-ray diffraction (XRD) and optical analyses, focusing on the effects of varying copper acetate((CH3 .COO)2 Cu·H2 O ) as the Cu precursor concentrations., hydrazine (N2 H5 OH) as a complexion agent, and ammonium hydroxide (NH4 OH) as a pH regulator at a bath temperature of 80°C. The films were deposited by adding 1ml, 2ml, 3ml, 4ml, and 5 ml of 0.4 M copper acetate to the bath solution. The films were smooth, well-adherent, uniform, and thick. The films were characterized by X-ray diffraction for structural study and UV-VIS spectrophotometer for the study of optical properties. The XRD study revealed that the films deposited with 1 to 3 ml of copper acetate solution crystallized in the monoclinic phase of the CuO structure, with two prominent peaks at 35.5° and 38.7°, which are indexed to the (002) and (111) planes of the monoclinic CuO structure. The films deposited with 4 and 5 ml of copper acetate had an additional peak at 36.5°, which is indexed to the (111) plane of cubic Cu2 O. Optical studies revealed that the CuO thin films have a direct band transition with values of 2 eV, 1.85 eV, 1.8 eV, 1.95 eV, and 2.2eV for CuO thin films deposited with 1 ml, 2 ml, 3 ml, 4 ml, and 5 ml of copper acetate, respectively
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    INVESTIGATION OF STRUCTURAL AND OPTICAL PROPERTIES OF MANGANESE DOPED COPPER OXIDE THIN FILM SYNTHESIZED BY CHEMICAL BATH DEPOSITION METHOD
    (HAWASSA UNIVERSITY, 2024-11) DESALEGN FENTAHUN TADEGE
    This study investigates the synthesis and characterization of manganese-doped copper oxide (CuMnO) thin films deposited onto glass substrates using the chemical bath deposition (CBD) method. The objective were to understand how varying manganese concentrations affect the structural and optical properties of the films. The process involved preparing solutions with varying manganese sulfate concentrations (1.5 ml, 3 ml, 4.5 ml, and 6 ml) and maintaining constant conditions for copper acetate, ammonia and hydrazine. The films were deposited at 50°C for 30 minutes, followed by annealing at a temperature of 300°C for 1 hours and 30 minutes. Structural analysis using X-ray diffraction (XRD) revealed that the films possessed a monoclinic copper manganese oxide and cubic Cu2O structure .The crystallite size initially increased with manganese concentration, reaching a maximum at 4.5 ml, before slightly decreasing. The dislocation density and strain showed corresponding trends, indicating improved crystal quality up to a certain concentration. Optical properties were assessed using UV-Vis spectroscopy. The band gap of the films increased from 1.7 eV to 1.9 eV as the manganese concentration rose from 1.5 ml to 6 ml. This shift in the band gap reflects the impact of manganese doping on the electronic structure of the films, potentially enhancing their suitability for optoelectronic applications. Overall, the results demonstrate that manganese doping effectively tunes the structural and optical characteristics of CuMnO thin films, offering insights into their potential use in various technological applications, including sensors and photovoltaic devices
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    THE EFFECT OF DEPOSITION TEMPERATURE ON STRUCTURAL AND OPTICAL PROPERTIES OF CdS THIN FILM BY USING CHEMICALBATH DEPOSITION METHOD
    (HAWASSA UNIVERSITY, 2024-04) Dawit Ewnetie Temesgen
    Cadmium sulphide is an intrinsic n-type semiconductor material with the chemical formula CdS. CdS thin films where deposited on glass substrates using cadmium sulphate as the cadmium ion source, thiourea as the sulphur source, and ammonia as the complexing agent through the chemical bath deposition method . The effect of deposition temperature ranging from 400C to 800C in 100C intervals on the structural and optical properties of thin films was investigated. The films were annealed at 3000C for 1:30 hours. The CdS thin films were characterized using XRD for structure and UV-VIS spectrophotometer for optical property determination. Optical investigations revealed that CdS exhibited high absorption in the visible region, with the optical band gap from 1.80 eV to 1.37 eV as the temperature increased. This indicates an inverse relationship between deposition temperature and band gap energy, making these thin films suitable as absorber materials for solar cell fabrication. XRD analysis showed that the deposited CdS thin films had a simple hexagonal crystal structure with preferred orientation along the (002) plane. The intensity of the sharp peak indicates that the sample is highly crystalline. Additionally, the crystalline size of the CdS thin films increased with the higher bath temperatures. Generally, varying the deposition temperature had effect on the structural and optical properties of cadmium sulphide thin films.
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    EFFECT OF THIOUREA CONCENTRATION ON THE STRUCTURAL AND OPTICAL PROPERTIES OF PbS THIN FILMS SYNTHESIZED BY CHEMICAL BATH DEPOSITION METHOD
    (HAWASSA UNIVERSITY, 2024-11) ADDISU MINAYEHU ENGIDA
    In the present work lead sulfide (PbS) thin films were synthesized on glass substrate by chemical bath deposition method as material employing lead acetate as a source of Pb2+ and thiourea as a source of precursor S2- and sodium hydroxide as complexing agent in the solution of distilled water. The thin film have been deposited at constant bath temperature of 800c and the deposition time was 20 minute for different samples in the various 0.2M thiourea concentrations of 8, 9, 10, 11 and 12 mL respectively. The thin films were characterized by using X – ray diffraction and UV – Vis spectrophotometer. X-ray diffraction analyses revealed that all the films were polycrystalline in nature with the diffraction peaks indices to the face centred cubic structure. For as the deposited thin films, it revealed that PbS nanocrystalline with preferred orientation along the (111) for 8 mL which changes to (200) for 9 – 12 mL in per set of 1 mL for various thiourea concentration due to the change of the total system free energy during the film growth. The structural parameters, such as the lattice constant (a), crystallite size (D), dislocation density (ρ) and micro strain (ε) were evaluated from the XRD spectra. The average crystalline size was calculated using the Debye – Scherer’s formula and found to decrease from 35.71 to 29.64 nm with an increase thiourea concentration in the case of increasing the growth rate, at fast deposition rate and growing species has no enough time to be organized. The dislocation density and micro strain were found to vary inversely with the crystallite size, whereas the lattice constant was found to decrease with a decrease of in crystallite size. The UV – Vis spectroscopy characterization of the sample revealed that the optical band gap of energy was increased from 1.55 to 1.61 eV with increasing thiouera concentration due to the quantum size effect of polycrystalline PbS thin film. Keywords: Chemical bath deposition, Lead sulphide, thin films