Raman and Photoluminescence Study of ZnO Films Grown by Chemical Method

In this paper phonon and emission properties of ZnO films grown by metalorganic chemical vapour deposition (MOCVD) at ambient pressure and by molecular beam epitaxy (MBE) are investigated using Raman and photoluminescence (PL) spectroscopy. It is shown that high-frequency shift of non-polar phonon modes corresponds to elastic compressive strain in the plane parallel to c-axis and is equal to 3.2×10−3 and 2.2×10−3 for ZnO film grown by MOCVD and MBE, respectively. The possibility of obtaining highquality ZnO films grown by MOCVD was demonstrated. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3501

Investigation of luminescent properties inherent to SrTiO₃:Pr³⁺ luminophor with Al impurity

The red-emitting SrTiO₃:Pr³⁺,Al luminophors that can be used for the white light emitting diodes (LEDs) were prepared using the sol-gel method. The starting materials were SrCl₂, Ti (O – i – C₃H₇)₄, Al(NO₃)₃·9H₂O and PrCl₃. The reaction between them results in a mixture of compounds that transform into single-phase SrTiO₃:Pr³⁺,Al after annealing in air. Displacement of Ti out of the SrTiO₃ lattice caused by substitution with Al and formation of individual crystalline TiO₂ phase (rutile) were observed. PL spectra show the high-intense red peak (λ = 617 nm), the same high-intense peak with the full width at half maximum (FWHM) 20 nm was found in cathodoluminescence spectra. The increase of the aluminium concentration from 0 up to 15 mol.% leads to approximately two-fold increase in the luminance. The latter increases from 180 up to 350 cd/m² at the anode voltage 10 kV and current density 30 μA/cm²

Investigation of growth conditions, crystal structure and surface morphology of SmS films fabricated by MOCVD technique

The polycrystalline SmS films were fabricated by MOCVD technique using a number of ditiocarbamates, synthesized by different techniques. The growth kinetics and temperature dependencies of the film growth rate are investigated, which allowed us to determine the activation energies and the reaction type. The investigations of the structure and surface morphology of films were carried out. The technological conditions are determined providing the fabrication of single-phase SmS films of cubic modification with the most ordered crystal structure

SrTiO₃:Eu³⁺ phosphors prepared by sol-gel synthesis: Structural characterization, magnetic properties and luminescence spectroscopy study

We report the results of the comprehensive study of the structural, magnetic and optical properties of SrTiO₃ perovskite doped with Eu³⁺ ions. Polycrystalline powders were obtained by sol-gel process including high-temperature annealing at 1300 °C. The structural analysis showed that material is composed of several phases with dominant SrТiO₃ and onsiderable quantity of titanium dioxide (rutile, 10…20%). Both the amount of Eu and ratio of Eu:Sr in the final product are considerably smaller as compared to the original solutions for synthesis. The elemental analysis reveals europium only in the phase of EuSrTi₂O₇ compound for equimolar ratio of Eu and Sr during the synthesis. The EPR analysis reports deficiency of Eu²⁺ in the samples under investigations. SrTiO₃:Eu³⁺ powders demonstrate weak photoluminescence, which intensity grows up with increasing the concentration of Eu and reaches its maximum at c.a. 8 mol.% of Eu in the original solutions. Addition of Al increases the intensity of photoluminescence (c.a. 2.2 for 10 mol.%). Emission spectra are typical for Eu³⁺ occupied sites with high symmetric environment (dominant ⁵D₀→⁷F₁ transition) with relatively low distortion (both ⁵D₀→⁷F₂ and ⁵D₀→⁷F₄ as well present, but with a lower intensity) of coordination polyhedron. Low solid-solubility limit of Eu³⁺ in perovskite matrix (less than 1 mol.%), peculiarities of optical spectra, effect of Al, production/annealing temperature dependence etc. have suggested that structural effects are dominating in functional, in particular, optical properties of SrTiO₃:Eu³⁺ phosphors

Composite film structures containg ZnS, CdS nanoparticles prepared by MOC pyrolysis at low temperatures

New composite structures containing ZnS, CdS nanoparticles were prepared with bright light-blue colour of a luminescence. The structures were formed by spraying organic solution of zinc or cadmium ditiocarbamate onto substrates at temperatures within the range 40…120°C. It was established that the film emission maximum monotonously shifts into short-wave spectral region at the decreasing substrate temperature: from 590 nm (Ts = 120°C) to 500 nm (Ts = 50°C) for ZnS and from 510 nm (Ts = 120°C) to 450 nm (Ts = 40°C) for CdS. This fact can be explained by the quantum size effect: X-ray analysis has shown that researched films contain crystalline particles of 1…5 nm size

Experience in the Use of Psychocorrection Therapy in the Comprehensive Treatment of Patients with Gastroesophageal Reflux Disease Combined with Dysfunction of the Biliary System

Nowadays, due to the rapid increase in the number of stress factors, it is especially important to use psychotherapy and psychopharmacotherapy in the combination treatment of patients with diseases of the gastrointestinal tract. Psychogenic overlaying plays a leading role in the clinical picture of the disease and determines the decreased performance in patients. Objective. To evaluate the effectiveness of therapy with psychocorrective agents in patients with gastroesophageal reflux disease (GERD) associated with dysfunction of the biliary system, if they have depressive and anxiety symptoms. Materials and methods. All patients were divided into 2 groups: group I consisted of 27 patients, who received only basic combination treatment, group II — of 25 patients, who in addition to the basic treatment received thioridazine, which is a piperidine derivative of phenothiazine and belongs to the group of neuroleptics. Both groups were representative by the age, duration and course of the disease. All patients demonstrate anxiety and depressive symptoms on the HADS scale. Questionnaire SF‑36 was used to analyze the quality of life. Treatment efficacy was assessed 14 days after. Results. As a result of the treatment, an improvement in overall well-being was observed in both groups against the background of reduction in the pain and dyspeptic syndromes. Additional prescription of psychocorrectives (thioridazine) to the basic therapy results in greater positive changes in the intensity of anxiety and depressive symptoms. The distribution of patients by the level of anxiety and depression after treatment showed that these indicators were absent more often in group II (by 2.6 and 1.5 times, respectively). However, cases of clinically significant anxiety and depression were 4.6 and 3.7 times more often in patients, who did not receive thioridazine. The difference in points between the level of anxiety and depression before and after the treatment was 4 times higher in patients, who additionally received psychocorrection. Also, comparing scores before and after the treatment, we have found significant improvement in the quality of life in group II. Conclusion. The inclusion of thioridazine into the basic therapy in the presence of depressive and anxiety disorders in patients with GERD associated with dysfunction of the biliary system improves the clinical effectiveness of pharmacotherapy of this comorbid pathology

Semiconductor surface spectroscopy using transverse acousto-electric effect: Role of surface charge in photo-processes at the ZnS/Si interface

The effect of illumination in the visible spectral range on the magnitude of transverse acoustoelectric effect (TAE) in ZnS/Si structures was studied using a noncontact surface acoustic wave device based on the acoustoelectronic structure with an air gap. ZnS films were obtained using pyrolysis of the chelate organometallic complex, zinc diethyldithiocarbamate, on Si substrates within the temperature range 220 to 260 °С. It has been established that the charge of the adsorption origin on the external surface of the ZnS film strongly influences the photo-processes in the structure under consideration. For the samples with a small surface charge, the value of TAE decreases rapidly with the increase in illumination power due to an increase in the concentration of non-equilibrium carriers. For the samples with a large surface charge, the barrier-trap mechanism of photogeneration is observed, in which the appearance of non-equilibrium carriers is accompanied by their capture and subsequent thermalization. This compensating mechanism explains well both stabilization of the magnitude of TAE by a distributed system of traps with rather large capacitance, and the specific shape of dependence of the TAE magnitude on illumination power. The technique developed by us on the basis of the transverse acoustoelectric effect in the layered piezodielectric / air-gap / semiconductor structure is a powerful tool for non- contact determination of the charge state of film structures, depending on their deposition parameters and various external conditions

Efficiency of Combined Hepatoprotector Forceliv in the Treatment of Chronic Diffuse Liver Disease

The article presents the results of a study of serum alanine aminotransferase levels in patients with chronic diffuse liver diseases on the background of combined hepatoprotector Forceliv application. According to the findings, a significant decrease of this indicator in all examined patients has been found, that confirms the efficiency of the above mentioned hepatoprotector