Cadmium sulfide (CdS) thin films with n-type semiconductor characteristics were prepared by flash evaporating method on glass substrates. Some films were annealed at 250 oC for 1hr in air. The thicknesses of the films was estimated to be 0.5µ by the spectrometer measurement. Structural, morphological, electrical, optical and photoconductivity properties of CdS films have been investigated by X-ray diffraction, AFM, the Hall effect, optical transmittance spectra and photoconductivity analysis, respectively. X-ray diffraction (XRD) pattern shows that CdS films are in the stable hexagonal crystalline structure. Using Debye Scherrerś formula, the average grain size for the samples was found to be 26 nm. The transmittance of the samples was determined from optical trasmittance spectra. It is observed that the direct band gap energy for as deposited and annealed films are (2.55, 2.45) eV, respectively. The effect of annealing at 250 oC for 1hr in air on optical and photoconductivity of films under various intensity of illuminations (43.81 and 115.12) mW/cm2 was studied. The dark and photocurrents of the annealed films were found to be greater than that of as deposited.
In This paper, CuO thin films having different thickness (250, 300 , 350 and 400) nm were deposited on glass substrates by thermal vacuum evaporator. The thermal oxidation of this evaporated film was done in heated glass at temperature (300 in air at one hour. The study of X-ray diffraction investigated all the exhibit polycrystalline nature with monoclinic crystal structure include uniformly grains. Thin film’s internal structure topographical and optical properties. Furthermore, the crystallization directions of CuO (35.54 , 38.70 ) can be clearly observed through an X-ray diffraction analysis XRD, Atomic Force Microscope AFM (topographic image) showed that the surface Characteristics , thin films crystals grew with increases in either
... Show MoreZinc sulfide(ZnS) thin films of different thickness were deposited on corning glass with the substrate kept at room temperature and high vacuum using thermal evaporation technique.the film properties investigated include their absorbance/transmittance/reflectance spectra,band gap,refractive index,extinction coefficient,complex dielectric constant and thickness.The films were found to exhibt high transmittance(59-98%) ,low absorbance and low reflectance in the visible/near infrared region up to 900 nm..However, the absorbance of the films were found to be high in the ultra violet region with peak around 360 nm.The thickness(using optical interference fringes method) of various films thichness(100,200,300,and 400) nm.The band gap meas
... Show MoreThe optical detectors which had been used in medical applications, and especially in radioactive treatments, need to be modified studied for the effects of radiations on them. This study included preparation of the MnS thin films in a way that vacuum thermal evaporation process at room temperature 27°C with thickness (400+-10nm) nm and a sedimentation rate of 0.39nm/sec on glass floors. The thin films prepared as a detector and had to be treated with neutron irradiation to examine the results gained from this process. The results decay X-ray (XRD) showed that all the prepared thin films have a multi-crystalline structure with the dominance of the direction (111), the two samples were irradiated with a neutron irradiation source (241Am-9Be)
... Show MoreExplain in this study, thickness has an inverse relationship with electrical resistivity and a linear relationship with Grain boundary scattering. According to the (Fuchs-Sondheier, Mayadas-Shatzkces) model, grain boundary scattering leads To an Increase in electrical Resistivity. The surface scattering Coefficient of Ag, which Fuchs-Sondheier and Mayadas-Shatzkces measured at , Ag's grain boundary reflection coefficient , which Mayadas-Shatzkces measured at , If the concentration of material has an effect on metal's electrical properties, According to this silver is a good electrical conductor and is used frequently in electrical and electronic circuits.
Nanocomposites of polymer material based on CdS as filler
material and poly methyl methacrylate (PMMA) as host matrix have
been fabricated by chemical spray pyrolysis method on glass
substrate. CdS particles synthesized by co-precipitation route using
cadimium chloride and thioacetamide as starting materials and
ammonium hydroxide as precipitating agent. The structure is
examined by X-ray diffraction (XRD), the resultant film has
amorphous structure. The optical energy gap is found to be (4.5,
4.06) eV before and after CdS addition, respectively. Electrical
activation energy for CdS/PMMA has two regions with values of
0.079 and 0.433 eV.
Titanium dioxide (TiO2) Nano powder has been synthesized by hydrothermal method. The reaction took place between titanium tetrachloride (TiCI4) and mixture solution consisted of deionized water and ethanol, in the ratio (3:7) respectively. Structure and surface morphology of TiO2 Nano powder at different annealing temperatures in the range 200-800°C for 120 min were characterized by X-ray diffraction (XRD), Atomic Force Microscope (AFM), Scanning Electron Microscopy (SEM), FT-IR and UV/visible spectroscopy measurements. The results show that with an increase in annealing temperature, the value of the intensity of (110) peak for rutile phase increases while the value of the full-width at half maximum (FWHM) decreases, and the band gap de
... Show MoreIn this work, MWCNT in the epoxy can be prepared at room temperature and thickness (1mm) at different concentration of CNTs powder. Optical properties of multi-walled carbon nanotubes (CNTs) reinforced epoxy have been measured in the range of (300-800)nm. The electronic transition in pure epoxy and CNT/epoxy indicated direct allowed transition. Also, it is found that the energy gap of epoxy is 4.1eV and this value decreased within range of (4.1-3.5)eV when the concentration of CNT powder increased from (0.001-0.1)% respectively.
The optical constants which include (the refractive index (n), the extinction coefficient (k), real (ε1) and imaginarily (ε2) part of dielectric constant calculated in the of (300-800)nm at different concent