ОСОБЕННОСТИ ФОРМИРОВАНИЯ ТОНКИХ ПЛЕНОК КРЕМНИЯ, ОСАЖДАЕМЫХ МАГНЕТРОННЫМ РАСПЫЛЕНИЕМ

The surface morphology and optical properties of Si coatings formed by magnetron sputtering were studied using atomic force microscopy, scanning electron microscopy, and spectrophotometry methods. The possibility to influence the surface morphology of coating (filamentous structures and/or round holes) and the location of maxima and minima in reflectance and transmittance via a controllable variation of magnetron sputtering regimes (substrate temperature and bias potential) is shown. Методами атомно-силовой и сканирующей электронной микроскопии, а также спектрофотометрии исследованы морфология поверхности и оптические характеристики тонких Si-покрытий, сформированных методом магнетронного распыления. Показано, что при контролируемой вариации технологических параметров магнетронного распыления таких, как температура подложки и потенциал смещения, можно менять морфологию поверхности пленок Si. Для некоторых режимов осаждения обнаружено появление на поверхности нитевидных структур и/или круглых углублений, изменения положения минимумов и максимумов в оптических спектрах отражения и пропускания.

Physical Background for Luminescence Thermometry Sensors Based on Pr3+:LaF3 Crystalline Particles

The main goal of this study was creating multifunctional nanoparticles based on rare-earth doped LaF3 nanocrystals, which can be used as fluorescence thermal sensors operating over the 80–320 K temperature range including physiological temperature range (10–50°C). The Pr3+:LaF3 (CPr = 1%) microcrystalline powder and the Pr3+:LaF3 (CPr = 12%, 20%) nanoparticles were studied. It was proved that all the samples were capable of thermal sensing into the temperature range from 80 to 320 K. It was revealed that the mechanisms of temperature sensitivity for the microcrystalline powder and the nanoparticles are different. In the powder, the 3P1 and 3P0 states of Pr3+ ion share their electronic populations according to the Boltzmann and thermalization of the 3P1 state takes place. In the nanoparticles, two temperature dependent mechanisms were suggested: energy migration within 3P0 state in the temperature range from 80 K to 200 K followed by quenching of 3P0 state by OH groups at higher temperatures. The values of the relative sensitivities for the Pr3+:LaF3 (CPr = 1%) microcrystalline powder and the Pr3+:LaF3 (CPr = 12%, 20%) nanoparticles into the physiological temperature range (at 45°C) were 1, 0.5, and 0.3% °C−1, respectively

Coprecipitation Method of Synthesis, Characterization, and Cytotoxicity of Pr 3+

The Pr3+:LaF3 (CPr = 3, 7, 12, 20, 30%) nanoparticles were characterized by means of high-resolution transmission electron microscopy, X-ray diffraction, optical spectroscopy, energy dispersive X-ray spectroscopy, dynamic light scattering, and MTT assay. It was revealed that the average diameter of all the NPs is around 14–18 nm. The hydrodynamic radius of the Pr3+:LaF3 (CPr = 7%) nanoparticles strongly depends on the medium. It was revealed that hydrodynamic radii of the Pr3+:LaF3 (CPr = 7%) nanoparticles in water, DMEM, and RPMI-1640 biological mediums were 18 ± 5, 41 ± 6, and 186 ± 8 nm, respectively. The Pr3+:LaF3 (CPr = 7%) nanoparticles were nontoxic at micromolar concentrations toward COLO-320 cell line. The lifetime curves were fitted biexponentially, and for the Pr3+:LaF3 (CPr = 7%) NPs, the luminescence lifetimes of Pr3+ ions were 480 ± 2 and 53 ± 5 nanosec