Effect of the microwave radiation treatment of porous indium phosphide on spectra of radiative recombination centers

To study the influence of microwave irradiation on a spectrum of defect states in porous InP, we have measured the luminescence spectra within the range 0.50 to 2.04 eV at 77 K before and after short and long (up to 600 s) treatments in air in the operation chamber of a magnetron at a frequency of 2.45 GHz and a surface power density of 7.5 W/cm² . We have obtained that the spectra of defects in researched samples are essentially changed as well as the concentrations of local centers. Possible mechanisms of observable changes in the semiconductor impurity-defect composition caused by a microwave treatment are discussed

Effect of weak magnetic fields treatment on photoluminescence of III-V single crystals

The long-term transformations of photoluminescence of GaP, GaAs and InP single crystals treated with pulsed weak magnetic fields are obtained. The treatments were performed in two regimes, namely, single-pulse (τ = 30 ms) and multi-pulse (τ = 1.2 ms) ones, at varying magnitudes of magnetic induction. The defect structure transformations were inferred from the radiative recombination spectra in the 0.6-2.5 μm at 77 K. A possible mechanism of observed modifications related to the electron spin transformation is discussed

Influence of treatment in weak magnetic fields on photoluminescence of GaN:Si

The long-term transformations of photoluminescence of GaN:Si treated with pulsed weak magnetic fields have been studied. The defect structure transformations have been inferred from the radiative recombination spectra within the range 350…650 nm at 300 K. A possible mechanism of observed modifications related with the magnetic field induced destruction of metastable complexes has been discussed

Characteristics of Nanocrystalline Zirconia Powder in the ZrO2- Y2O3-CeO2-Al2O3 system with 0.1wt.% СоО

Matrix (mol%) 95ZrO2-3Y2O3-2CeO2 was produced by hydrothermal synthesis from a mixture of previously precipitated hydroxides. -Al2O3 and Co(NO3)3 were added by mechanical mixing. The properties of nanocrystalline powders with a complex chemical composition (wt.) [90 (ZrO2-CeO2-Y2O3)-10Al2O3]-(0,1Al2O3-0,1CoO) after heat treatment in the temperature range from 400 to 1300 °C were investigated by XRD phase analysis and BET measurements. During heat treatment powders retained in nanocrystallite state (primary particle size of the zirconia solid solution varies from 14 to 83 nm), and its specific surface area decreases from 99,7 m2/g to 1.51 m2/g. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3526

Екологічні особливості та біоіндикаційне значення черепашкових амеб (Testacea, Rhizopoda) у природних і антропогенно трансформованих біогеоценозах

The literature data on physiology and ecology characteristics of testate amoebas Testacea, Rhizopoda were reviewed. The testate amoebas can be used as the bioindicators of the different soil conditions in natural biogeocenoses. The data of using the superclass Rhizopoda members as indicators of anthropogenic influences on soil are given. Проаналізовано фізіологічні та екологічні особливості черепашкових амеб Testacea, Rhizopoda. Підкреслено, що тестації можуть виступати біоіндикаторами різноманітних ґрунтових умов у природних біогеоценозах. Наведено дані з використання представників надкласу Rhizopoda як показників антропогенного впливу на ґрунти. Проаналізовано фізіологічні та екологічні особливості черепашкових амеб Testacea, Rhizopoda. Підкреслено, що тестації можуть виступати біоіндикаторами різноманітних ґрунтових умов у природних біогеоценозах. Наведено дані з використання представників надкласу Rhizopoda як показників антропогенного впливу на ґрунти.

Influence of pulse magnetic fields treatment on optical properties of GaAs based films

Long-term transformations of the optical reflectance of GaAs epitaxial structure under weak magnetic field treatment (B = 60 mT, f = 10 Hz, τ = 1.2 ms, t = 5 min) have been obtained. Optical measurements were performed within the wavelength range 800…1100 nm at 300 K. Non-monotonous changes of reflectance were observed. Experimental results have been interpreted in terms of diffusion of point defects, resulting from destruction of metastable complexes (probably [VAs+impurity]), from the internal boundaries to the surfaces of the investigated structures. The method for detection of non-equilibrium complexes in multilayer objects has been proposed

Effect of low magnetic field treatment on spectra of radiative recombination centers in indium phosphide structures

We present the results of investigations of the effect caused by low magnetic field treatment on InP single crystals impurity-defect composition. This effect was found when studying the radiative recombination (luminescence) spectra in the 0.6-2.5 µm range at 77 K. The static magnet with B = 0.44 T was used as a source of magnetic field. We studied samples of two groups: porous InP crystals and epitaxial layers grown on porous substrate. The crystals of both groups were not specially doped. It has been obtained that treatment even for 0.02 min resulted in considerable changes in luminescence spectra. The luminescence intensities after treatment increase at first, but later behavior is nonmonotonic: next treatment can result in decrease or increase a value of intensities of both observed bands. It should be noted that the luminescence intensities of epitaxial layers, perhaps, changed as well as concentration of nonradiative centers changed. But for porous indium phosphide, these features were not observed

Effect of pulsing magnetic field on radiative recombination spectra of GaP and InP single crystals

We present the results of investigations concerning the effect caused by weak magnetic field (B = 15 mT and 60 mT) treatment on GaP and InP single crystals of impurity-defect composition. This effect was found when studying the radiative recombination (luminescence) spectra within the range 0.6 to 2.5 µm at 77 K. It was obtained that a short-term influence of field initiates long-term changes in the intensity of radiative recombination inherent to centers of different nature. General regularities in behavior of the luminescence intensity have been found. This intensity changes with the concentration of recombination centers. A possible mechanism of observed transformations has been discussed

Physical mechanisms and models of the long-term transformations in radiative recombination observed in n-GaAs under microwave irradiation

Simulation of long-term changes in photoluminescence of n-GaAs after microwave treatment by using the analysis of random events underlying the processes of evolution of the defect structure has been performed. We have shown the agreement of the experimental and theoretical time dependences of the changes in the photoluminescence intensity provided that the distribution of the random variable – time to a random event – obeys the Weibull–Gnedenko law. The mechanisms of transformation of the defect structure, which are based on the dynamics of behavior of dislocations and impurity complexes owing to microwave irradiation, have been presented

Physical mechanisms and models of long-term transformations of radiative recombination in n-GaAs due to the magnetic field treatments

Simulation of long-time changes in photoluminescence of n-GaAs has been performed, and the mechanism of transformation of the defect structure caused by magnetic field treatments has been represented