Annealing Effect on the Structural and Optical Properties of Sol- Gel Deposited Nanocrystalline CdO Thin Films

In this paper CdO thin films have been prepared by using SOL-GEL method with spin coating technique, by depoited four layers  of mixtuer solution contians Cadmium acetate dehydrate, Triethylamine, glycerol and ethanol.The spin coated solution were dried at 100°C and annealied at (300,350 and 400 oC temperatures ). The x-ray diffraction techniques and UV-VIS spectrophotometer have confirmed the structural and the optical properties the prepared thin films. CdO thin films were found to have polycrystalline nature with cubic rock salt phase. The crystallinity being improved, the FWHM decreases and the grain size of the CdO thin films increased with increasing the annealing temperatures. The average grain size is observed in the range  (23.97 - 30.47) nm which indicate that the prepared film have a nanocrystalline structure. From optical analysis, it can be seen that there are an increases in the absorbance and decreases in the trancemittance  of the prepared films with the increasing of the annealing temperatures.The optical band gap decreases  from 2.556, to 2.081 eV with increasing of annealing temperature fromm 300 to 400° C, this suggested that the optical band gap for CdO nanocrystalline thin films is strongly dependent on the annealing temperature. Keywords: CdO thin films, Sol–gel spin–coating, Structural and Optical properties, annealing temperature

Structure, surface topography and optical characterization of Ag co – doped Cd1-xCuxO nanostructure thin films

Cd1-xCuxO and Ag co-doped Cd1-xCuxO nanostructure thin films with x = 0.2 and different Ag content (0-8%) were deposited by chemical spray pyrolysis technique on glass substrates at a temperature of 350 oC. The XRD results showed that the prepared films have polycrystalline with low crystallinity nature for CdO cubic structure. The preferential orientation of all films was absorbed along (111) plane. CuO monoclinic phase has appeared with low intensity while the Ag cubic phase appeared only in 8% of Ag content. Structural parameters such as average crystallite size, dislocation density and micro-strain were also investigated. SEM images revealed that the surface morphology of the films consists of spherical shaped grains uniformly distributed without detectable micro-cracks and improved by Ag Co-doping. EDXS spectrum analysis confirmed purity and stoichiometry of the prepared compositions. AFM results showed that the surface topography and the surface quality of the deposited thin films can be controlled by the variation of the Ag co-doping concentration. Optical absorbance and transmittance of Ag co-doped Cd1-xCuxO thin films has high values in the visible and near infrared regions respectively and varied with Ag co-doping content. Direct optical energy band gap of Cd1-xCuxO exhibits a blue shift with Ag co-doping, due to the quantum size and Burstein–Moss (BM) effects. The increasing of optical energy gap was confirmed by the decrease in the Urbach tails energy EU after Ag co-doping.

Rheological and optical characterization of Polyvinylpyrrolidone (PVP) - Polyethylene glycol (PEG) polymer blends

Polymer blends of different concentrations for PVP-K30 and different additive weights of PEG8000 have been prepared as polymeric blends solutions. The rheological and optical properties of the blends samples have been investigated using Ostwald viscometer and Refractometer. The results showed that the density, shear, relative and specific viscosities are increases with the increasing of PVP concentration and additive weight of PEG. The optical constant values such as refractive index, reflectance, molar reflectance, coefficient of finesse and Brewster Angle are increase with the increasing of PVP concentration and additive weight of PEG while the critical angle has the revers behavior. DOI: http://dx.doi.org/10.31257/2018/JKP/2019/11020