Кафедра "Природничі науки"

Постійне посилання колекціїhttps://repository.kpi.kharkov.ua/handle/KhPI-Press/1703

Увага! Поповнення колекції кафедри "Природничі науки" від травня 2023 року тимчасово призупинено.

Офіційний сайт кафедри http://web.kpi.kharkov.ua/ken

Кафедра "Природничі науки" заснована в 1973 році.

Кафедра забезпечувала викладання дисциплін природничого циклу іноземним громадянам, які готуються продовжувати навчання у вищих навчальних закладах України.

Студенти отримують необхідний рівень знань з природничих дисциплін і мають можливість вступати в будь-які вузи України для подальшого навчання.

Кафедра входить до складу Навчально-наукового інституту міжнародної освіти Національного технічного університету "Харківський політехнічний інститут".

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The influence of physical and technological magnetron sputtering modes on the structure and optical properties of CdS and CdTe films
(Інститут фізики напівпровідників ім. В. Є. Лашкарьова, 2017) Khrypunov, G. S.; Kopach, G. I.; Harchenko, M. M.; Dobrozhan, A. I.
To create technology for preparation of CdS and CdTe thin films by direct current magnetron sputtering, the influence of physical and technological condensation modes on the crystal structure and optical properties of these films were investigated. The laboratory method of DC magnetron sputtering with preheating of the target for the mentioned films on glass substrates was developed. We obtained the CdS layers with hexagonal structure 150…200 nm thick under conditions when the plasma discharge current density was 1.1 mA/cm² and the deposition rate – 30…40 nm/min. The bandgap in the obtained CdS films is Eg = 2.38…2.41 eV. After annealing in vacuum, the optical transparence of CdS films reaches 80…90%, which allows to use these films as a transparent window layer in solar cells based on heterojunctions of CdS/CdTe. When the plasma discharge current density is 2.2…5.4 mA/cm² and the deposition rate is 200 nm/min, we obtained CdTe layers with hexagonal structure up to 5 μm thick. The transmittance of CdTe films with hexagonal structure in the wavelength range of the visible spectrum is up to 5%, and in the infrared spectral range is about 60%. The bandgap in the obtained CdTe layers of different thickness is 1.52…1.54 eV. After chloride treatment as a result of the phase transition wurtzite-sphalerite, the investigated CdTe films contain only the stable cubic structure and can be used as a base layer of solar cells.
Properties of CdTe Films Prepared By DC Magnetron Sputtering
(Institute of Electrical and Electronics Engineers, 2017) Kirichenko, Michailo Valerievich; Zaitsev, Roman Valentinovich; Dobrozhan, A. I.; Khrypunov, Gennadiy Semenovich; Harchenko, M. M.
In order to create thin-film solar cells based on cadmium sulfide and telluride experimental studies of the process of cadmium telluride magnetron sputtering with direct current, and the impact of a magnetron sputtering mode on CdTe films crystalline structure were carried out. CdTe films for the base layers of thin film solar cells was obtained on flexible polyimide substrates by magnetron sputtering with direct current for the first time. It has found that increasing the magnetron discharge current up to 80 mA leads to increase in coherent scattering regions what is due to an increase in the thickness of the cadmium telluride films of the hexagonal modification having a columnar structure. A further increase in the discharge current leads to a decrease in the size of coherent scattering regions what caused by the thermodynamical output formation of low-angle boundaries. It has shown experimentally that the "chloride" processing of the obtained cadmium telluride layer leads to the transformation of the metastable hexagonal modification cadmium telluride in a stable cubic modification. At the same time, due to the eutectic recrystallization, increase in the sizes of coherent scattering regions by a decade and the microstrain level reduction in 1.5 times are observed.
Structure and Optical Properties CdS and CdTe Films on Flexible Substrate Obtained by DC Magnetron Sputtering for Solar Cells
(Сумський державний університет, 2017) Kopach, G. I.; Mygushchenko, R. P.; Khrypunov, G. S.; Dobrozhan, A. I.; Harchenko, M. M.
The paper describes investigate of crystal structure and optical characteristics of the CdS transparent window layers and the CdTe base layers, obtained by direct current magnetron sputtering on glass or polyimide substrate, and output parameters the flexible thin film solar cells based on them. The band gap in obtained hexagonal CdS films is Eg = 2.38-2.41 eV and optical transparency of CdS films is 80-90%. Conducting chloride treatment of CdTe layers, obtained at Tп < 300 °C, promotes wurtzite-sphalerite phase transition. Cooling ITO/CdS layers to room temperature before CdTe deposition, removal of the air and subsequent heating in vacuum to the required temperature of the substrate leads to an increase of the energy conversion efficiency and open circuit voltage of the polyimide/ITO/CdS/CdTe/Cu/Ag flexible solar cell.
Structure and Optical Properties CdS and CdTe Films on Flexible Substrate Obtained by DC Magnetron Sputtering for Solar Sells
(Прикарпатський національний університет ім. Василя Стефаника, 2017) Kopach, G. I.; Mygushchenko, R. P.; Khrypunov, G. S.; Dobrozhan, A. I.; Harchenko, M. M.
Structure and Optical Properties of CdS Nanoscale Thin Films Obtained by Direct Current Magnetron Sputtering
(Institute of Electrical and Electronics Engineers, 2017) Kopach, G. I.; Mygushchenko, R. P.; Khrypunov, G. S.; Dobrozhan, A. I.; Harchenko, M. M.
The influence of physical and technological condensation mode by direct current magnetron sputtering with preheating of the target on the crystal structure and optical properties of grown CdS nanoscale thin films was investigated. CdS layers on glass substrates with hexagonal structure 80-100 nm thick under conditions plasma discharge current density is 1.1 mA/cm² and the deposition rate is 18-20 nm/min were obtained. The band gap CdS in nanoscale thin films is Eg=2,4-2,43 eV. After annealing in vacuum optical transparency of CdS films is 90%, which allows to use such nanoscale thin films as a transparent window layer in solar cells based on heterostructure of CdS/CdTe.
Study Solid Solutions in CdS/CdTe Thin Films Heterosystems Obtaine by DC Magnetron Sputtering
(Institute of Electrical and Electronics Engineers, 2018) Dobrozhan, A. I.; Kopach, G. I.; Mygushchenko, R. P.; Khrypunov, G. S.; Harchenko, M. M.; Polezhaeva, O. V.
The influence of physical and technological condensation mode by direct current magnetron sputtering on the crystal structure and optical properties of grown CdS and CdTe films, CdS/CdTe thin films heterosystems was investigated. Traditional chloride treatment of thin-film CdS/CdТе heterosystem leads to recrystallization of CdTe basic layer and its wurtzite-sphalerite phase transition. After Cl treatment a bandgap in CdTe increases up to 1.5 eV. For CdS/CdТе heterosystem a decrease of a bandgap to 1.45 eV is observed which is determined by formation of solid solutions of CdSхТе₁₋ₓ at the interphase boundary of CdS/CdТе. The value of the stoichiometric parameter х=0,1±0,01 was calculated using the optical researches data.
The effect of UV and glow-dischare hydrogen plasma irradiation on the crystalline structure and efficiency of CdTe/CdS thin film solar cells prepared by the quasi-closed volume method
(Scientific and Technological Corporation "Institute for Single Crystals", 2021) Harchenko, M. M.; Meriuts, A. V.; Nikitin, A. V.; Surovitskiy, S. V.; Dobrozhan, A. I.; Buts, Y. V.
It is shown that the crystal structure and photoelectric properties of CdTe/CdS-based solar cells (SCs), fabricated by condensation in a quasi-closed volume, change their characteristics the action of irradiation with a high-dose hydrogen plasma flux.