New Trends in Lithium Niobate: From Bulk to Nanocrystals

Aerosol-Assisted Chemical Vapor Deposition (AACVD) Technique of SrTiO3: B Thin Films and Study the Structural and Optical Properties and Hall Effect Measurements

Aerosol-assisted chemical vapor deposition (AACVD) technique is very precise implemented to fabrication of structured SrTiO3 and Sr1-xBxTiO3 thin films at doping ratio (x = 2, 4, 6 and 8) % at temperature 400 °C on a glass substrate. The X-Ray Diffraction (XRD) patterns illustrated that the SrTiO3 and Sr1-xBxTiO3 thin films have a polycrystalline nature and cubic structure, the detailed characterization of the films by X-ray diffraction (XRD), the Surface Morphology studied by using (AFM) and (SEM). Have been noticed from AFM measurement the Roughness and RMS were increased with increases doping ratio. The optical properties of SrTiO3 and Sr1-xBxTiO3 thin films have been studied at doping ratio (x = 2, 4, 6 and 8) % at rate (300-900) nm. The transmittance spectrum is characterized by the opposite behavior of the absorbance spectrum. The transmittance generally increases with the increase in the wavelength of radiation, at wavelengths with low energies while the absorbance decreased slowly at spectrum rate (300-900) nm i.e. in the visible region. The band gap (Eg) is decreased at (3.2 - 2.5) eV which indicates that the doping process has led to the emergence of localized levels in the region confined by the valence and conduction bands, led to a reduction in the photon energy required for direct electronic transitions to occur. Found the carriers concentration charge are holes of Sr1-xBxTiO3 thin films at doping ratio (x = 2, 4, 6 and 8) %. Many properties can be improved by adding impurities such as Boron (B) to the SrTiO3, which can be used in solar cells, electronic industries or thermoelectric generators by controlling the optical or structural properties of the material by controlling the materials and percentages of impurity, or through heat treatment of the material, such as annealing, for example or exposure to different temperatures.

Radiation Modification of Optical Characteristics of LiNbO3:Zn and LiNbO3:Mg Crystals

The modification of the optical characteristics of LiNbO3:Zn and LiNbO3:Mg crystals grown by the Czochralski method was investigated using β and γ radiation. The photorefractive effect was found to be inhibited by ionizing radiation in the LiNbO3:Zn ([ZnO] ≈ 2.1 mol%) crystal, which belonged to a below-threshold concentration range. The inhibition was attributed to a stepwise radiation annealing of charged defects. Ionizing radiation increased the general optical uniformity of above-threshold crystals LiNbO3:Zn ([ZnO] ≈ 5.9 mol%) and LiNbO3:Mg([MgO] ≈ 5.6 mol%). In addition, we determined that radiation annealing substantially influenced photorefraction dynamics in lightly doped LiNbO3:Zn ([ZnO] ≈ 0.1 mol%) crystals, which widens their application areas.