Thin films of Zinc Oxide (ZnO) having different concentrations were deposited using the Aqueous Chemical Growth (ACG) method. The films were characterized using Rutherford Back Scattering (RBS) spectroscopy for chemic...Thin films of Zinc Oxide (ZnO) having different concentrations were deposited using the Aqueous Chemical Growth (ACG) method. The films were characterized using Rutherford Back Scattering (RBS) spectroscopy for chemical composition and thickness, X-Ray Diffraction (XRD) for crystallographic structure, a UV-VIS spectrophotometer for the analysis of the optical and solid state properties which include spectral absorbance, transmittance, reflectance, refractive index, direct band gap, real and imaginary dielectric constants, absorption and extinction coefficients and a photomicroscope for photomicrographs. The average deposited film thickness was 100 nm. The results indicate that the values of all the optical and solid state properties investigated vary directly with concentration except transmittance which is the reverse. Thus, the optical and solid state properties of ZnO thin film deposited by the Acqueous Chemical Growth method can be tuned by deliberately controlling the concentration of the precursors for various optoelectronic applications including its application as absorber layer in solar cells.展开更多
Thin films of hematite (α-Fe2O3) were deposited by heteronucleation through the process of hydrolysis and condensation of an aqueous solution of 0.1 M Fe (NO3)3.9H2O, 1 M NaNO3, 50 ml H2O in addition with five drops ...Thin films of hematite (α-Fe2O3) were deposited by heteronucleation through the process of hydrolysis and condensation of an aqueous solution of 0.1 M Fe (NO3)3.9H2O, 1 M NaNO3, 50 ml H2O in addition with five drops of HCl at 90℃. One of the samples was kept as prepared while the others were annealed at different temperatures in order to determine the effect of annealing on their solid state and optical properties. The films were characterized using Rutherford Back Scattering (RBS), spectroscopy for chemical composition and thickness, X-Ray Diffraction (XRD) for structural analysis, UV-VIS Spectrophotometer for the analysis of other solid state and optical properties and a photomicroscope for photomicrographs. The results indicate that while the absorbance and absorption coefficient decreases with increasing annealing temperature, the direct band gap and refractive index increases with increasing annealing temperature in the direction of increasing photon energy in the visible range. Also, there is a high infrared transmittance which increases with increasing annealing temperature and a shift/decrease in peak value of all the optical properties except transmittance in the direction of increasing photon energy as annealing temperature increases. The results further indicate that ACG hematite thin film annealed at 632K is a suitable metal oxide semiconductor material for photocatalytic applications. It is also suitable for use in the construction of poultry houses for the rearing of chicks because of its high infrared transmittance including other opto-electronic applications.展开更多
文摘Thin films of Zinc Oxide (ZnO) having different concentrations were deposited using the Aqueous Chemical Growth (ACG) method. The films were characterized using Rutherford Back Scattering (RBS) spectroscopy for chemical composition and thickness, X-Ray Diffraction (XRD) for crystallographic structure, a UV-VIS spectrophotometer for the analysis of the optical and solid state properties which include spectral absorbance, transmittance, reflectance, refractive index, direct band gap, real and imaginary dielectric constants, absorption and extinction coefficients and a photomicroscope for photomicrographs. The average deposited film thickness was 100 nm. The results indicate that the values of all the optical and solid state properties investigated vary directly with concentration except transmittance which is the reverse. Thus, the optical and solid state properties of ZnO thin film deposited by the Acqueous Chemical Growth method can be tuned by deliberately controlling the concentration of the precursors for various optoelectronic applications including its application as absorber layer in solar cells.
文摘Thin films of hematite (α-Fe2O3) were deposited by heteronucleation through the process of hydrolysis and condensation of an aqueous solution of 0.1 M Fe (NO3)3.9H2O, 1 M NaNO3, 50 ml H2O in addition with five drops of HCl at 90℃. One of the samples was kept as prepared while the others were annealed at different temperatures in order to determine the effect of annealing on their solid state and optical properties. The films were characterized using Rutherford Back Scattering (RBS), spectroscopy for chemical composition and thickness, X-Ray Diffraction (XRD) for structural analysis, UV-VIS Spectrophotometer for the analysis of other solid state and optical properties and a photomicroscope for photomicrographs. The results indicate that while the absorbance and absorption coefficient decreases with increasing annealing temperature, the direct band gap and refractive index increases with increasing annealing temperature in the direction of increasing photon energy in the visible range. Also, there is a high infrared transmittance which increases with increasing annealing temperature and a shift/decrease in peak value of all the optical properties except transmittance in the direction of increasing photon energy as annealing temperature increases. The results further indicate that ACG hematite thin film annealed at 632K is a suitable metal oxide semiconductor material for photocatalytic applications. It is also suitable for use in the construction of poultry houses for the rearing of chicks because of its high infrared transmittance including other opto-electronic applications.
