Applied Physics
Teymur B. Taghiyev
Abstract
The study investigated the photoluminescent properties of undoped and rare-earth element erbium-doped solid solutions GaS1-xSex0.1аt% irradiated with gamma-quanta. Erbium doping reduces the photoluminescence intensity in solid solutions. After irradiation Dg= 300-1000Gy, the photoluminescence intensity ...
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The study investigated the photoluminescent properties of undoped and rare-earth element erbium-doped solid solutions GaS1-xSex0.1аt% irradiated with gamma-quanta. Erbium doping reduces the photoluminescence intensity in solid solutions. After irradiation Dg= 300-1000Gy, the photoluminescence intensity increases. An increase in the photoluminescence intensity in irradiated solid solutions is explained by a decrease in the concentration of centres responsible for the fast recombination channel and associated with lattice defects. At T=77K, due to the decay of bound Frenkel pairs, Si and Vs appear in the sulfur sublattice. The Si defects are responsible for the increase in the intensity of the green luminescence band. The redistribution of photoluminescence intensity in the 0.520 - 0.600 µm range is due to energy transfer to rare-earth centres in activated crystals. The investigated results allow us to conclude that doping with erbium leads to a series of emission lines appearing in the visible region of the spectrum.
Nanotechnology
Reem A. Saleh; Odai N. Salman; Mohammed O. Dawood
Abstract
In this work, well-oriented and homogeneous titanium dioxide (TiO2) nanorods (NRs) was synthesized by hydrothermal method. In this method, vertically aligned arrays of TiO2 were built on the conductive Fluorine–Tin–Oxide (FTO) glass substrate. Nanoparticles (NRs) of TiO2 showed a tetragonal ...
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In this work, well-oriented and homogeneous titanium dioxide (TiO2) nanorods (NRs) was synthesized by hydrothermal method. In this method, vertically aligned arrays of TiO2 were built on the conductive Fluorine–Tin–Oxide (FTO) glass substrate. Nanoparticles (NRs) of TiO2 showed a tetragonal shape with a square top face, according to the image of the field emission scanning electron microscope (FE-SEM). The TiO2 NRs are polycrystalline, having two phases: rutile and anatase, according to X-ray diffraction (XRD) analysis. The optical properties of a TiO2 nanorods arrays were examined, including transmittance, absorption coefficient, and energy bandgap. An optical energy band gap of 3.18 eV was obtained. According to the photoluminescence emission measurement, the energy bandgap was 3.3 eV. For further study of the optical properties of the TiO2 Nanorods films, reflectance spectrum was used as a function of wavelength to estimate the value of the energy bandgap and its value was 3.45 eV. By comparing the values obtained from the three methods, it is found that they are closely alike, which confirms the formation of the TiO2 nanostructure.
