Перегляд за Автор "Vlasov, Andriy"

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Barrier structures on the basis of graded-band-gap CdHgTe obtained by evaporation-condensation-diffusion method
(2016) Świątek, Z.; Vlasov, Andriy; Ivashko, M.; Petryna, R.; Bonchyk, A.; Sokolovskii, B.; Власов, Андрій; Петрина, Роман
The paper presents the methods of obtaining photovoltaic structures based on CdXHg1- XTe graded-band-gap epitaxial layers. Barriers in these structures were formed by solid phase doping of the material with low-diffusing impurities (As). High-temperature diffusion of acceptor impurity (As) in intrinsically defective material of n-type conductivity as well as ion introducing the donor impurity (B) in uniformly doped during the epitaxy process material of p-type of conductivity have been used. The possibility of creating multi-element graded-band-gap photovoltaic structures suitable for broad band detection of infrared radiation as a result of epitaxial growth by evaporation-condensation-diffusion method has been demonstrated.
Barrier structures on the basis of graded-band-gap CdHgTe obtained by evaporation-condensation-diffusion method
(2016) Świątek, Z.; Vlasov, Andriy; Ivashko, M. V.; Petryna, R. L.; Bonchyk, A. Yu.; Sokolovskii, B. S.
Conductivity type conversion in p- CdXHg1-XTe
(2003) Berchenko, N.; Bogoboyashchiy, V.; Izhnin, I.; Vlasov, Andriy; Kurbanov, K.; Yudenkov, V.; Берченко, Н.; Богобоящий, В.; Іжнін, І.; Власов, Андрій; Курбанов, К.; Юденков, В.
Investigations and comparative analysis of p-to-n type conductivity conversion processes on the identical samples of vacancy doped p-CdxHg–xTe (x 0.2) under ion-beam milling (IBM) and anodic oxide annealing and on the identical samples of As-doped p-CdxHg1–xTe (x 0.22) under IBM and anodic oxide annealing have been carried out. The conductivity type conversion has been observed at the considerable depth of the vacancy doped material both under IBM or under anodic oxide annealing while in the case with As-doped material only under IBM. It was considered that conversion in all these processes was determined by the mercury interstitial diffusion from corresponding mercury diffusion source and recombination with its native acceptors – cationic vacancies (in the first case) or with donor complex formations (in the second one). It has been shown that in the vacancy-doped p-CdxHg1–xTe the effective diffusion coefficients for the mercury interstitials that determines the depth of the converted layer are equal each other at equal temperatures either under thermal annealing in the saturated mercury vapour or anodic oxide annealing. It proves the identity of the mercury concentration in the diffusion source. Absence of the conversion under anodic oxide annealing in the As-doped p-CdxHg1–xTe is explained by insufficient Hg concentration in the source and it matches well with necessary condition for donor complex formation as it takes place under IBM.
Controlled arsenic diffusion in epitaxial CdXHg1-XTe layers in the evaporation-condensation-diffusion process
(2002) Vlasov, Andriy; Pysarevsky, V.; Storchun, O.; Shorchenko, A.; Bonchyk, A.; Pokhmurska, H.; Barcz, A.; Swiatek, Z.; Власов, Андрій; Писаревський, В.; Сторчун, О.; Шорченко, А.; Бончик, А.; Похмурська, Г.; Святек, З.
The results of controlled doping of CdxHg1yxTe epitaxial layers are presented. The investigated layers were obtained by the evaporation–condensation–diffusion method in the process of isothermal growth. The process of auto diffusion from the solid phase was investigated. This process consists in the diffusion of As dopants from CdTe substrate into the grown epitaxial layer. Two types of CdTe substrates, uniformly doped in the process of synthesis and unalloyed with ion implanted surface layer, have been used as sources of As diffusant. Comparative analysis of galvanomagnetic measurements and SIMS spectra was carried out. The results of investigations indicate the very high, almost 100%, electrical activity of As dopants in the CdxHg1yxTe epitaxial grown layer. 2002 Elsevier Science B.V. All rights reserved.
Defect Structure Rebuilding by Ion Beam Milling of As and Sb Doped p-Hg1–xCdxTe
(2002) Berchenko, N.; Bogoboyashchiy, V.; Izhnin, I.; Vlasov, Andriy; Берченко, Н.; Богобоящий, В.; Іжнін, І.; Власов, Андрій
This study focuses on developing an understanding of the mechanisms of ion beam milling induced p-to-n conversion in extrinsically (As or Sb) doped p-Hg1––xCdxTe with x 0.2. The basis of modeling is the quasichemical approach and the model of superfast Hg interstitial atoms diffusion that has permitted to explain the similar conversion occurred in Hg vacancy-doped p-type Hg1––xCdxTe. In an acceptor doped material a donor is generated due to the formation of a complex (of interstitial Hg atom and an As or Sb atom located in the Te site). This model provides reasonably good fits with the experimental results obtained for As and Sb doped Hg1––xCdxTe epitaxial layers where the electron concentration in the converted n-layer corresponds to the concentration of the p-type dopants. Different efficiency of the conductivity conversion observed for As and Sb doped samples may be explained by different enthalpy of complex formation calculated for AsTe–HgI and SbTe– HgI pairs.
High temperature arsenic doping of CdHgTe epitaxial layers
(2004) Vlasov, Andriy; Bogoboyashchiy, V.; Bonchyk, O.; Barcz, A.; Власов, Андрій; Богобоящий, В.; Бончик, О.
Experimental results on solid-state arsenic doping of the n-type bulk and ISOVPE epitaxial CdXHg1-XTe (X = 0.19÷0.3) alloys are presented. The arsenic doped thin epitaxial CdxHg1-xTe films (nAs ≈ 5⋅1016÷1⋅1020 cm-3; d =2÷5 μm) obtained by RF sputtering in a mercury glow discharge were used as As diffusion sources. The arsenic diffusion and activation were carried out at temperatures Т = 500÷600°С under Hg vapour pressure. Immediately after the high temperature treatment all samples were annealed to annihilate point defects. The SIMS analysis was used for determination of the quantitative admixture distribution of As in the diffusion area. The arsenic electrical activity has been evaluated by means of differential Hall, resistivity and thermoemf measurements. The analysis of experimental data obtained as well as their comparison with previously obtained results has been performed.
Influence of laser shock waves on As implanted HgCdTe
(2007) Yakovyna, V.; Berchenko, N.; Kuzma, M.; Vlasov, Andriy; Яковина, В.; Берченко, Н.; Кузма, М.; Власов, Андрій
The principal purpose of our research is to show that low-temperature treatment of materials can be successfully used instead of annealing. Laser shock waves (LSW) were chosen as an alternative to form p-n junctions in HgCdTe after arsenic ions were implanted. Electrical characteristics of As implanted HgCdTe bulk crystals were studied to determine the effect of LSW generated by nanosecond laser irradiation pulses. The samples were of n-type conductivity immediately after the implantation. Then LSW processing was performed under increasingly growing laser beam power density and shock wave pressure. The experiment demonstrated that a threshold shock wave pressure should be reached to ensure the p-to-n conductivity conversion in the surface layer of samples. On the whole the results provide evidence that LSW combined with ion implantation can be used to form p-n junctions in HgCdTe
Reconstruction of lattice structure of ion-implanted near-surface regions of Hg1 − XCdXTe epitaxial layers
(2008) Vlasov, Andriy; Bonchyk, O.; Kiyak, S.; Fodchuk, I.; Kazemirskiy, T.; Barcz, A.; Zieba, P.; Swiatek, Z.; Maziarz, W.; Власов, Андрій
The results of X-ray, SIMS, SEM and AFM studies of near-surface regions of Hg1 − XCdXTe (111) and (110) structures have been presented. These structures were obtained during annealing in the vapour of main components of ISOVPE Hg1 − XCdXTe epitaxial layers with the surface implanted with arsenic ions. Berg-Barrett topography method and two-crystal spectrometry technique were exploited. For calculation of depth dependences of deformations and concentrations of dominating defects in the layer's near-surface regions, the Takagi-Taupin equation and generalized dynamic theory of X-ray scattering were used. From experimental SIMS analysis, the distributions of both impurity and main components of Hg1 − XCdXTe solid solution were determined providing more accurately the deformation profiles in near-surface regions of the structures. SIMS and SEM analyses have given evidence of abrupt gradients of content in the Hg1 − XCdXTe solid solution, due to small changes of thermodynamical equilibrium conditions of high-temperature annealing in the near-surface regions. These are the cause of formation of a gradedgap structure with strains in the crystal lattice. AFM studies have demonstrated that the morphology of Hg1 − XCdXTe structures is subjected to the influence of CdTe substrate orientation.
Relaxation of electrical properties of n-type layers formed by ion milling in epitaxial HgCdTe doped with V-group acceptors
(2006) Bogoboyashchyy, V.; Izhnin, I.; Mynbaev, K.; Pociask, M.; Vlasov, Andriy
The relaxation of electrical properties of As- and Sb-doped HgCdTe epitaxial layers, which were converted into n-type by ion milling, is studied. It is shown that donor complexes formed under ion milling and responsible for p-to-n conductivity type conversion are not stable, and their concentration decreases upon storage even at room temperature. Increasing the temperature of the storage speeds up the relaxation process. It is demonstrated that the relaxation is caused by the disintegration of the donor complexes that starts right after the end of the milling process because of the decrease in the concentration of interstitial mercury atoms, which were generated during the milling. The results presented in the paper are important for the development of the technology of photodetectors based on HgCdTe doped with V-group acceptors.
The controlled doping and structural homogeneity of CdHgTe epitaxial layers=Kontrolowane domieszkowanie i jednorodność strukturalne warstw epitoksjalnych CdHgTe
(2007) Vlasov, Andriy; Bonchyk, O.; Fodchuk, I.; Zaplitnyy, R.; Barcz, A.; Swiatek, Z.; Litynska-Dobrzynska, L.; Zieba, P.; Bielanska, E.; Guspiel, J.; Власов, Андрій
X-ray diffraction methods as well as atomic force microscopy (AFM) and secondary ion mass spectroscopy (SIMS) were used to study the controlled doping and structural homogeneity of HgCdTe epitaxial layers. The investigated layers were obtained by the evaporation-condensation-diffusion (ECD) method in the process of isothermal growth. Two types of substrates for CdHgTe ECD growth were used: (110) and (111) CdTe monocrystals with As ion implanted surface layer at a dose of 1×1015cm−2 and an energy of 100 keV. Structural changes in damaged areas of CdTe crystals that arise at the ion beam implantation and the influence of radiation defects on the quality of obtained layers are analyzed
Time Relaxation of Point Defects in p- and n-(HgCd)Te after Ion Milling
(2003) Belas, E.; Bogoboyashchyy, V.; Grill, R.; Izhnin, I.; Vlasov, Andriy; Yudenkov, V.; Белас, Е.; Богобоящий, В.; Гріл, Р.; Іжнін, І.; Власов, Андрій; Юденков, В.
RH(77 K) of the n-type layer created by ion milling is investigated in Hg vacancy-doped, As-doped, and In-predoped p-type, and In-doped n-type Hg1−xCdxTe (0.2 < x < 0.22) samples. We show that the n-type layer is formed, and the temperature-activated relaxation occurs in all cases. The annealing at 75°C results in a gradual degradation of the converted n-type layer and a back n-to-p conversion within 8 days. The existence of a high-conducting, surfacedamaged region with a high-electron density (∼1018 cm−3) and a low mobility (∼103 cm2/Vs) is confirmed, and its influence on the relaxation is studied.
Робоча програма навчальної дисципліни "Спортивна метрологія" галузі знань 01 "Освіта" напряму підготовки 014.11 “Середня освіта (фізична культура)”
(2017) Власов, Андрій; Vlasov, Andriy
Метою викладання навчальної дисципліни “Спортивна метрологія" є формування у студентів системи знань, навиків і умінь у галузі спортивних вимірювань, що є необхідним елементом професійного становлення тренера, викладача фізичної культури.
Робоча програма навчальної дисципліни "Спортивна метрологія" галузі знань 01 "Освіта" напряму підготовки 017 "Фізична культура і спорт"
(2017) Власов, Андрій; Vlasov, Andriy
Метою викладання навчальної дисципліни “Спортивна метрологія” є формування у студен-тів системи знань, навиків і умінь у галузі спортивних вимірювань, що є необхідним елементом професійного становлення тренера, викладача фізичної культури.
Спортивна метрологія : програма навчальної дисципліни підготовки бакалаврів напряму підготовки 017 “Фізична культура і спорт”
(2017) Власов, Андрій; Vlasov, Andriy
Метою викладання навчальної дисципліни “Спортивна метрологія" є формування у студентів системи знань, навиків і умінь у галузі спортивних вимірювань, що є необхідним елементом професійного становлення тренера, викладача фізичної культури.
Спортивна метрологія : програма нормативної навчальної дисципліни підготовки бакалаврів напряму підготовки 014.11 “Середня освіта (фізична культура)”
(2017) Власов, Андрій; Vlasov, Andriy
Метою викладання навчальної дисципліни “Спортивна метрологія” є формування у студентів системи знань, навиків і умінь у галузі спортивних вимірювань, що є необхідним елементом професійного становлення тренера, викладача фізичної культури.