ABSTRACT ZnO/NiO multilayer thin films were obtained using chemical bath deposition method. The p... more ABSTRACT ZnO/NiO multilayer thin films were obtained using chemical bath deposition method. The precursor solution used were nickel sulphate and zinc nitrate. The effect of annealing temperature on the optical properties and band-gap energy were studied by annealing the deposited films at different temperatures of 100 o C and 300 o C. Optical properties such as absorbance and transmittance were determined using Unico UV-2102 PC spectrophotometer, at normal incidence of light in the wavelength range of 200-1000nm. The band-gap energy was discovered to lie between 2.00-2.50 eV. The composition of the deposited firm was also obtained.
ABSTRACT Thin films of CdS were doped with Co to form CdCoS ternary thin films. The films were de... more ABSTRACT Thin films of CdS were doped with Co to form CdCoS ternary thin films. The films were deposited on glass substrate using the solution growth technique at room temperature from aqueous solution of CdCl 2 , thiourea and CoCl 2 . Optical properties such as absorbance and transmittance were determined using Unico UV-2102 PC Spectrophotometer, at normal incidence of light in the wavelength range of 200-1000nm. From absorbance and transmittance spectra, the band gap energy was determined. The band gap energy was found in the 2.10 to 2.60eV range. The result shows that deposition time influences both the optical properties and band-gap energy of the films.
ABSTRACT A nanocrystalline and porous p-polyaniline/n-WO3 dissimilar heterojunction at ambient te... more ABSTRACT A nanocrystalline and porous p-polyaniline/n-WO3 dissimilar heterojunction at ambient temperature is reported. The high-quality and well-reproducible conjugated polymer composite films have been fabricated by oxidative polymerization of anilinium ion on predeposited WO3 thin film by chemical bath deposition followed by thermal annealing at 573 K for 1 h. Atomic force microscopy (AFM) analyses reveal a homogenous but irregular cluster of faceted spherically shaped grains with pores. The scanning electron microscopy confirms the porous network of grains, which is in good agreement with the AFM result. The optical absorption analysis of polyaniline/WO3 hybrid films showed that direct optical transition exist in the photon energy range 3.50–4.00 eV with bandgap of 3.70 eV. The refractive index developed peak at 445 nm in the dispersion region while the high-frequency dielectric constant, ɛ ∞, and the carrier concentration to effective mass ratio, N/m*, was found to be 1.58 and 1.10 × 1039 cm−3, respectively. The temperature dependence of electrical resistivity of the deposited films follows the semiconductor behavior while the C–V characteristics (Mott–Schottky plots) show that the flat band potential was −791 and 830 meV/SCE for WO3 and polyaniline.
Antimony sulphide (Sb2S3) and Thallium Sulphide (Tl2S) thin films each were deposited from aqueou... more Antimony sulphide (Sb2S3) and Thallium Sulphide (Tl2S) thin films each were deposited from aqueous baths on glass substrates. Thin films of antimony sulphide (Sb2S3) were deposited from a bath containing antimony trichloride dissolved in acetone and Sodium thiosulphate. Thin films of thallium sulphide (Tl2S) were deposited from a bath containing thallium nitrate, sodium citrate, sodium hydroxide and thiourea. Some of the films produced were annealed in oven for 2hours at various temperatures. Multilayer films of Sb2S3-Tl2S and Tl2S-S2S3 were also produced, and annealed for 2hours at 180 o C. The thin films produced were studied using XRD, spectrophotometer and optical microscope. From the transmittance spectra, the optical band gaps for the films were calculated. The values obtained for these materials are 1.40eV (Sb2S3), 1.30eV (Tl2S) and between 1.40 and 1.70eV for the multilayer films (Tl2S-Sb2S3). Some of the films have very poor transmittance and high absorbance values througho...
ABSTRACT ZnO/NiO multilayer thin films were obtained using chemical bath deposition method. The p... more ABSTRACT ZnO/NiO multilayer thin films were obtained using chemical bath deposition method. The precursor solution used were nickel sulphate and zinc nitrate. The effect of annealing temperature on the optical properties and band-gap energy were studied by annealing the deposited films at different temperatures of 100 o C and 300 o C. Optical properties such as absorbance and transmittance were determined using Unico UV-2102 PC spectrophotometer, at normal incidence of light in the wavelength range of 200-1000nm. The band-gap energy was discovered to lie between 2.00-2.50 eV. The composition of the deposited firm was also obtained.
ABSTRACT Thin films of CdS were doped with Co to form CdCoS ternary thin films. The films were de... more ABSTRACT Thin films of CdS were doped with Co to form CdCoS ternary thin films. The films were deposited on glass substrate using the solution growth technique at room temperature from aqueous solution of CdCl 2 , thiourea and CoCl 2 . Optical properties such as absorbance and transmittance were determined using Unico UV-2102 PC Spectrophotometer, at normal incidence of light in the wavelength range of 200-1000nm. From absorbance and transmittance spectra, the band gap energy was determined. The band gap energy was found in the 2.10 to 2.60eV range. The result shows that deposition time influences both the optical properties and band-gap energy of the films.
ABSTRACT A nanocrystalline and porous p-polyaniline/n-WO3 dissimilar heterojunction at ambient te... more ABSTRACT A nanocrystalline and porous p-polyaniline/n-WO3 dissimilar heterojunction at ambient temperature is reported. The high-quality and well-reproducible conjugated polymer composite films have been fabricated by oxidative polymerization of anilinium ion on predeposited WO3 thin film by chemical bath deposition followed by thermal annealing at 573 K for 1 h. Atomic force microscopy (AFM) analyses reveal a homogenous but irregular cluster of faceted spherically shaped grains with pores. The scanning electron microscopy confirms the porous network of grains, which is in good agreement with the AFM result. The optical absorption analysis of polyaniline/WO3 hybrid films showed that direct optical transition exist in the photon energy range 3.50–4.00 eV with bandgap of 3.70 eV. The refractive index developed peak at 445 nm in the dispersion region while the high-frequency dielectric constant, ɛ ∞, and the carrier concentration to effective mass ratio, N/m*, was found to be 1.58 and 1.10 × 1039 cm−3, respectively. The temperature dependence of electrical resistivity of the deposited films follows the semiconductor behavior while the C–V characteristics (Mott–Schottky plots) show that the flat band potential was −791 and 830 meV/SCE for WO3 and polyaniline.
Antimony sulphide (Sb2S3) and Thallium Sulphide (Tl2S) thin films each were deposited from aqueou... more Antimony sulphide (Sb2S3) and Thallium Sulphide (Tl2S) thin films each were deposited from aqueous baths on glass substrates. Thin films of antimony sulphide (Sb2S3) were deposited from a bath containing antimony trichloride dissolved in acetone and Sodium thiosulphate. Thin films of thallium sulphide (Tl2S) were deposited from a bath containing thallium nitrate, sodium citrate, sodium hydroxide and thiourea. Some of the films produced were annealed in oven for 2hours at various temperatures. Multilayer films of Sb2S3-Tl2S and Tl2S-S2S3 were also produced, and annealed for 2hours at 180 o C. The thin films produced were studied using XRD, spectrophotometer and optical microscope. From the transmittance spectra, the optical band gaps for the films were calculated. The values obtained for these materials are 1.40eV (Sb2S3), 1.30eV (Tl2S) and between 1.40 and 1.70eV for the multilayer films (Tl2S-Sb2S3). Some of the films have very poor transmittance and high absorbance values througho...
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