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  • Ескіз
    Документ
    Structure and properties of multi-period vacuum-arc coatings based on chromium nitride
    (Institute for Single Crystals, 2020) Postelnyk, H. O.; Sobol, O. V.; Kucerova, L.; Dur, Osman
    The properties of multi-period nanocomposite coatings based on chromium nitride are considered. The effect of the negative bias potential on the phase-structural state and mechanical characteristics of the coatings was investigated by X-ray diffractometry combined with the study of hardness by nanoindentation, surface roughness and coefficient of friction during scratch testing. It has been established that all the systems are characterized by the formation of a cubic crystal lattice of the structural type NaCl, as well as the effect of texture on hardness values. For the studied coatings, the hardness is in the range of 20-25 GPa. The presence of texture [311] in CrN/MoN nanocomposite coatings leads to the lowest friction coefficient with a value of about 0.2.
  • Ескіз
    Документ
    Physical and technological foundations of the "Chloride" treatment of cadmium telluride layers for thin-film photoelectric converters
    (Сумський державний університет, 2018) Kudii, D. A.; Khrypunov, M. G.; Zaitsev, R. V.; Khrypunova, A. L.
    The process of deposition of cadmium chloride films during the "chloride" treatment of cadmium telluride base layers for thin-film photoelectric converters (PEC) was studied. It is established that to ensure the reproducibility of the thickness and phase composition of cadmium chloride films, it is necessary to take into account the high hygroscopicity of this material. It is shown that the optimal growth rate of cadmium chloride films is 0.1 μm perminute. At high growth rates, cadmium chloride particulates are deposited on the surface of the CdTe layer base, which causes shunting of the PEC during the "chloride" treat-ment. It is determined that after the "chloride" treatment of CdTe layers, a coarse-grained structure is observed, which is predominantly oriented in the thermodynamic equilibrium direction. In this case, the average grain size increases to 5 μm. It is shown that when performing a "chloride" treatment, the optimum purity of cadmium chloride layers is 98 %, which is due to the doping of CdTe with copper atoms. The disadvantage of copper with the use of more pure cadmium chloride reduces the efficiency of the PEC due to the increase in the series resistivity and the decrease in the photocurrent density. It has been experimentally determined that the optimum thickness of cadmium chloride during the "chloride" treatment and the efficiency of the PEC obtained at the same time depends on the substrate used. Thus, for the ITO/CdS/CdTe/Cu/Au PEC, the optimum thickness of cadmium chloride is 0.40 μm, the efficiency is 9.6 %, and for the NaCl/ITO/CdS/CdTe/Cu/Au PEC – 0.10 μm and 6.4 %, respectively.
  • Ескіз
    Документ
    Amplitude-time characteristics of switching in thin films of cadmium telluride
    (Сумський державний університет, 2018) Khrypunov, M. G.; Zaitsev, R. V.; Kudii, D. A.; Khrypunova, A. L.
    The amplitudetime characteristics of switching in thin films of cadmium telluride were investigated when single impulses of 1 μs duration are applied. It has been experimentally established that with an increase in the thickness of the cadmium telluride layer from 3 μm to 8 μm, an increase in the operating threshold from 70 V to 105 V is observed. The maximum residual sample voltage varies from 12 V to 40 V, the minimum – from 5 V to 20 V. The switching time of the samples was no more than 2 nanoseconds; the interelectrode capacity of the samples was no more than 2 pF. All the test samples were operated without failure 20 times. The structural studies of cadmium telluride films by the method of X-ray diffractometry and scanning electron microscopy have made it possible to propose a mechanism for realizing the monostable switching of the columnar structure of cadmium telluride films oriented in the form of melted high-conductivity channels in grains oriented in the direction.
  • Ескіз
    Документ
    Структурно-фазовые превращения в многослойных периодических композициях W-B4C с периодом 2,5 НМ при нагреве
    (Харьковский национальный университет им. В. Н. Каразина; Научный физико-технологический центр МОН и НАН Украины, 2011) Копылец, Игорь Анатольевич; Зубарев, Евгений Николаевич; Кондратенко, Валерий Владимирович; Ананьев, К. А.
    В работе рентгеноструктурными и электронномикроскопическими методами изучались изменения в структуре и фазовом составе многослойной пленочной композиции, состоящей из чередующихся слоев W и B4C с толщиной бислоя 2,5 нм, при нагреве в вакууме в диапазоне температур 100 – 1000°С. Обнаружено, что в многослойном покрытии W-B4C при отжиге происходят следующие фазовые превращения: до 600°С образуются карбиды вольфрама (прежде всего W3C), свыше 600°С карбиды замещаются боридами W2B и WB, а при температуре выше 950°С образуются WB4 и W2B5. Эти превращения сопровождаются объемными изменениями: толщина слоев B4C уменьшается, а толщина W-содержащих слоев возрастает так, что при отжиге до 1000°С доля W-содержащего слоя в периоде увеличивается от 0,38 до 0,51. При этом величина периода до 600°С увеличивается на 1%, а при дальнейшем нагреве возвращается к приблизительно прежней величине. При 950 – 1000°С происходит разрушение многослойной структуры