Self-Organization of a 2D Lattice on a Surface of Ge Single Crystal after Irradiation with Yag: ND Laser

Experimentally observed self-organization of a 2D lattice on the surface of Ge single crystal after irradiation by pulsed YAG: Nd laser is repoted. The calculation of time depended distribution of temperature in bulk of the Ge sample show that overheating of the crystal lattice occurs at laser radiation intensities exceeding 30MW/cm2.The two temperature gradients are exists.Comment: Submitted on behalf of TIMA Editions (http://irevues.inist.fr/tima-editions

MODIFICATION OF BAND-GAP IN SURFACE LAYER OF CDZNTE BY YAG:Nd+3 LASER RADIATION

According to the effect, the interstitial atoms of Cd (Cdi) in Cd1-xZnxTe move along the temperature gradient while the Cd vacancies (VCd) and Zn atoms - in the opposite direction, into the bulk of the semiconductor where temperature is lower. Photoluminescence spectra studied at 5 K show that concentration of Cd atoms increases, but concentration of Zn atoms decreases at the surface due to redistribution atoms in temperature gradient of field. Formation of a graded band gap in Cd1- xZnxTe crystal at irradiation by the second harmonic of Nd:YAG laser is found

Properties of nanocones formed on a surface of semiconductors by laser radiation: quantum confinement effect of electrons, phonons, and excitons

On the basis of the analysis of experimental results, a two-stage mechanism of nanocones formation on the irradiated surface of semiconductors by Nd:YAG laser is proposed for elementary semiconductors and solid solutions, such as Si, Ge, SiGe, and CdZnTe. Properties observed are explained in the frame of quantum confinement effect. The first stage of the mechanism is characterized by the formation of a thin strained top layer, due to redistribution of point defects in temperature-gradient field induced by laser radiation. The second stage is characterized by mechanical plastic deformation of the stained top layer leading to arising of nanocones, due to selective laser absorption of the top layer. The nanocones formed on the irradiated surface of semiconductors by Nd:YAG laser possessing the properties of 1D graded bandgap have been found for Si, Ge, and SiGe as well, however QD structure in CdTe was observed. The model is confirmed by "blue shift" of bands in photoluminescence spectrum, "red shift" of longitudinal optical line in Raman back scattering spectrum of Ge crystal, appearance of Ge phase in SiGe solid solution after irradiation by the laser at intensity 20 MW/cm2, and non-monotonous dependence of Si crystal micro-hardness as function of the laser intensity

СИНТЕЗ И СТРУКТУРА ГАЗОЧУВСТВИТЕЛЬНЫХ КОМПОЗИТНЫХ МАТЕРИАЛОВ TIO2–MoO3

Introduction of molybdenum trioxide to gas sensing materials based on titanium dioxide results in a considerable increase of the output signal in the hydrogen-air environment. It is established that the value of the output signal reaches the maximum at the 1 mol. % MoO3 content in the composite material. Improved gas sensing characteristics of TiO2:MoO3 composite correlate with the structural and phase peculiarities of this system – the inhibition of TiO2 crystallization in the TiO2:MoO3 system, the shift of anatase-rutile phase transition to the higher temperature area in comparison with the temperature of this transition in unloaded TiO2, and with the presence of different types of tetrahonal distortions in MoO6 octahedrons, which ensures the MoO3 lattice high activity in the processes of hydrogen catalytic oxidation, and also with the crystallization of highly dispersed molybdenum oxide with a particle size of 10 nm.Введение легирующих добавок оксида молибдена в состав газочувствительных материалов на основе диоксида титана приводит к значительному повышению выходного сигнала в водородо-воздушной среде. Установлено, что величина выходного сигнала максимальна при содержании 1 мол. % МоО3 в композитном материале. Улучшенные газочувствительные характеристики композита TiO2–MoO3 с 1 мол. % МоО3 коррелируют со структурно-фазовыми особенностями данной системы – подавлением кристаллизации диоксида титана в системе TiO2–MoO3, смещением фазового перехода анатаз–рутил в область больших температур по сравнению с температурой данного перехода для нелегированного диоксида титана, наличием различных типов тетрагональных искажений в октаэдрах МоО6 по различным направлениям, обеспечивающих высокую активность кислорода решетки МоО3 в процессах каталитического окисления адсорбированных молекул водорода, а также кристаллизацией высокодисперсного оксида молибдена с размером частиц порядка 10 нм

Исследование методом атомно-силовой микроскопии влияния наночастиц на структурные и механические свойства клеток почки быка линии MDBK

The effect of copper and silver nanoparticles Cu+Ag, silver nitrite AgNO3 and zinc oxide ZnO on morphology and mechanical properties of immunocompetent cells bovine kidney line MDBK is investigated by atomic force microscopy. The results of calculation of the local elastic modulus, strength, surface cell adhesion, adhesion work, and the three-dimensional image analysis of cells in control and after incubation with the nanoparticles bioelements for 20 min are presented.Методом атомно-силовой микроскопии (АСМ) исследовано влияние наночастиц меди и серебра Cu+Ag, нитрита серебра AgNO3 и оксида цинка ZnO на морфологию и механические свойства иммунокомпетентных клеток почки быка линии MDBK. Представлены результаты расчетов локального модуля упругости, силы поверхностной адгезии клеток, работы адгезии, а также анализа трехмерных изображений клеток в контроле и после инкубации с наночастицами биоэлементов в течение 20 мин