Dariya Savchenko

National Technical University of Ukraine “Igor Sikorsky Kyiv Polytechnic Institute” · Department of General Physics and Modelling of Physical Processes

The nitrogen (N) donors in 6H SiC were investigated by field sweep electron spin echo (FS ESE), pulsed electron nuclear double resonance (ENDOR) and pulsed General TRIPLE ENDOR spectroscopy. The 29Si and 13C superhyperfine (shf) lines observed in the FS ESE and ENDOR spectra of N in n-type 6H SiC were assigned by pulsed General TRIPLE resonance spe...

The magnetic and electronic properties of heavily doped n-type 6H SiC samples with a nitrogen concentration of 1019 and 4 × 1019 cm−3 were studied with electron spin resonance (ESR) at 5–150 K. The observed ESR line with a Dysonian lineshape was attributed to the conduction electrons (CE). The CE ESR (CESR) line was fitted by Lorentzian (insulating...

The silicon carbide (SiC) 3C polytype microparticles with p‐type conductivity were investigated by X‐band electron paramagnetic resonance (EPR) technique in the wide temperature interval. Morphological and Raman studies showed that the mean diameter of the particles is ∽8 μm, and the SiC polytype is purely 3C. At T =10 K the EPR spectrum of the sha...

Semiconductor devices based on 15R silicon carbide (SiC) show improved properties compared to other polytypes. Here we report on the investigation of nitrogen-doped 15R SiC monocrystals with (ND – NA) ~ 5*10^18 cm^-3 using multi-frequency electron paramagnetic resonance (EPR) and electrically-detected magnetic resonance (EDMR) spectroscopic methods...

4H silicon carbide (SiC) polytype is preferred over other SiC polytypes for high-power, high-voltage, and high-frequency applications due to its superior electrical, thermal, and structural characteristics. In this manuscript, we provide a comprehensive study of the spin coupling dynamics between conduction electrons and nitrogen (N) donors in mono...

This work focuses on unraveling electron paramagnetic resonance (EPR) and electrically detected magnetic resonance (EDMR) properties of n -type 6 H silicon carbide (SiC) single crystals with high concentrations of uncompensated nitrogen (N) donors, which is essential for fundamental understanding of spin-related phenomena, developing spin-based dev...

We report the first study of Zn1−xMnxSe:Fe2+,Cr2+ (x = 0.3) crystals by continuous wave (CW) and pulsed electron paramagnetic resonance (EPR) spectroscopic techniques. Using the advantages of pulsed EPR, spin Hamiltonian parameters for Mn 2+ ions were obtained (g par= gper = 2.0060(3), Аpar = Аper = 61.84·10-4 cm-1 , and D =-7.1·10-4 cm-1). The tem...

Наведено у хронологічному порядку появу фундаментальних понять, законів та явищ, що передували відкриттю електронного парамагнітного резонансу (ЕПР) 21 січня 1944 року Є.К. Завойським. Наведено історію створення та розвитку наукової школи М.Ф. Дейгена

The imposition of martial law and power outages in Ukraine made the first semester of the 2022/2023 academic year at Igor Sikorsky Kyiv Polytechnic Institute a challenge for lecturers and students, especially in learning the general physics course. An asynchronous learning mode became the only possible form in such a situation, so the problem of in...

In this project, the temperature-dependent X-band EPR measurements will be performed on ZnO microparticles annealed in nitrogen and air atmosphere. Consequently, using EPR spectra modeling, the origin of each paramagnetic center will be established. As a result, the correlation between EPR data obtained in ZnO microparticles annealed in different c...

The radical scavenging activities of salicylaldehyde thiosemicarbazone and its copper(II) and cadmium(II) complexes were evaluated by in vitro experiments in the reaction with 2,2'-diphenyl-1-picrylhydrazyl. Salicylic aldehyde thiosemicarbazone complex with Cu(II) shows significantly higher radical-scavenging activity than Cu2+ ions, salicylaldehyd...

Carbon dots (CDs) fabricated using sucrose as a carbon source show intense photoluminescence and good biocompatibility, opening the perspective to use them in bioanalysis and biomarking. Furthermore, the sucrose-derived luminescent carbon dot-silica nanocomposites (CDs@SiO2) are novel nanomaterials that exhibit strong white light emission covering...

4H silicon carbide (SiC) polytype is preferred over other SiC polytypes for high-power, high-voltage, and high-frequency applications due to its superior electrical, thermal, and structural characteristics. In this manuscript, we provide a comprehensive study of the spin coupling dynamic between conduction electrons and nitrogen (N) donors in monoc...

Electrically detected magnetic resonance (EDMR) is an effective spectroscopic method utilized for characterizing semiconductive solid-state materials. High spin sensitivity and the capability to explore spin-dependent transport mechanisms, which are crucial for the development of semiconductor devices, defining it from other methods based on magnet...

The silicon carbide (SiC) single crystals of 6H polytype with nitrogen donor concentration (N D-N A) ≈ 1•10 17 ... 4•10 19 cm-3 grown using the modified Lely method were studied applying the cavity perturbation method. From the temperature dependence of the resonant frequency shift and microwave loss of the cavity loaded with samples under study, t...

The tumour suppressor p53 regulates the expression of a myriad of proteins that are important for numerous cellular processes, including apoptosis, cell cycle arrest, DNA repair, metabolism, and even autophagy and ferroptosis. Aside from DNA, p53 can interact with many types of partners including proteins and small organic molecules. The ability of...

Hydrogen‐free germanium (Ge)‐doped diamond‐like carbon (DLC) films deposited on SiO2 substrates are studied by electron spin resonance (ESR) technique at T = 5‐295 K. The Ge‐free and DLC films with 1 at. % and 2.5 at. % Ge content having low cytotoxicity are investigated. A single Lorentzian ESR line resulting from exchange interaction between loca...

The cadmium manganese telluride (Cd1-xMnxTe) crystals (x < 0.001 and x = 0.02, 0.04, 0.1) grown using the Bridgman method were studied by applying continuous wave and pulsed electron paramagnetic resonance (EPR) spectroscopy in the wide temperature range. The Cd1-xMnxTe crystals with x < 0.001 revealed the EPR spectrum from isolated Mn2+ with gper=...

Рекомендації до проходження практики студентів освітньо-професійної програми другого (магістерського) рівня вищої освіти «Комп’ютерне моделювання фізичних процесів» зі спеціальності 104 «Фізика та астрономія» розроблено відповідно до «Положення про порядок проведення практики здобувачів вищої освіти КПІ ім. Ігоря Сікорського»(наказ № 7/172 від 24.0...

Manganese-doped magnesium titanate ceramic samples obtained by a solid-state reaction via sintering in the air from a mixture of MgO and TiO 2 powders of different molar ratios were analyzed by electron paramagnetic resonance (EPR) technique. The EPR signals of Mn ²⁺ ions (S = 5/2, І = 5/2) in crystal phases of MgO, Mg 2 TiO 4 , and MgTiO 3 were de...

The paper considers the issue of organization of teaching physics to foreign students in higher education institutions of Ukraine at technical specialties in English language. In order to overcome the main difficulties in teaching foreign students (communication and linguistic barrier, psychological barrier, differences between the basic training o...

In the present work, a bottom-up approach to synthesize luminescent carbon dot-silica (CDs@SiO2) nanocomposites from the sucrose precursor was utilized. The sucrose concentration and thermal treatment effect on electron spin dynamics in CDs@SiO2 nanocomposites was investigated by electron spin resonance (ESR) technique. A single ESR line resulting...

Навчальний посібник містить методичні та інформаційні матеріали з дисципліни «Презентація результатів наукових досліджень». Метою посібника є ознайомлення аспірантів з загальними правилами оформлення результатів наукових досліджень, зокрема, наукових статей, тез, наукових доповідей, презентацій, дисертаційної роботи. Навчальний посібник буде корисн...

Посібник містить методичні вказівки до виконання самостійних робіт з навчальної дисципліни «Науково-дослідна робота за темою магістерської дисертації - 2. Науково-дослідна робота за темою магістерської дисертації». Метою посібника є ознайомлення студенів з загальними правилами оформлення результатів науково-дослідної роботи, зокрема наукових статей...

The paper analyzes up-to-date distance learning technologies used in European education system for ensuring overall organization of the educational process during the COVID-19 pandemic. Quarantine conditions have become a catalyst for development and practical testing of virtual learning tools and innovative pedagogical technologies, and applicatio...

Стаття звернена до проблеми організації навчального процесу у вищих навчальних закладах України в умовах карантинних заходів, коли традиційні форми очного навчання стають неможливими і необхідний швидкий, якісний та всебічний перехід до дистанційних форм навчання без втрат у змісті навчального процесу. Розглянуто, як виконав це завдання КПІ ім. Іго...

New data about the electronic state of Tb3+ doping ions in the Tb-doped EuAl3(BO3)4 and EuGa3(BO3)4 borate single crystals have been obtained from the electron paramagnetic resonance (EPR) spectra measurements at X- and Q-band frequency range in the wide temperature interval. Prior to the EPR study, the X-ray diffraction (XRD) techniques the struct...

Silica-carbon with zinc (SiO2:C:Zn) nanocomposites obtained via infiltration with aged luminescent zinc acetylacetonate (Zn(acac)2) ethanol solution of two concentrations (1 or 4%) into the fumed silica (SiO2) matrix have been studied using EPR within the temperature range 6…296 K before and after thermal annealing. The EPR spectrum of SiO2:C:Zn na...

Photoluminescent carbon nanodots (CDs), a new class of inorganic nanocarbon materials, have become a significant segments of luminescent nanomaterials in last decade. However mechanism of light emission and detailed identification of the light emitting centers is still debated. A huge number of synthesis methods were suggested, however few of them...

Метою посібника є ознайомлення студентів з основними функціями OriginPro для розв’язання конкретних прикладних задач. Особливу увагу приділено задачам візуалізації та обробки спектроскопічних даних. Навчальний посібник буде корисним студентам фізичних та технічних спеціальностей при обробці та візуалізації експериментальних даних, зокрема під час р...

Evolution of photoluminescence of ethanol solutions of Zn(acac) from near UV to VIS was monitored for time period of several months. It has been found that transparent solutions with time colored in light brown that is accompanied by development of strong visible photoluminescence. This phenomenon is analyzed and discussed in terms of carbon precip...

A complex EPR study of Iron-doped ZnSe single crystal that continues a series of works related to the magnetic properties of binary AIIBVI compounds doped with transition metals is presented. Even though the EPR studies of these compounds have been continuing for many years, the consensus about the nature and origins of the observed signals has no...

The magnetic and electronic properties of the hydrogenated highly conductive zinc oxide (ZnO) microparticles were investigated by electron paramagnetic resonance (EPR) and contactless microwave (MW) conductivity techniques in the wide temperature range. The EPR spectra simulation allowed us to resolve four overlapping EPR signals in ZnO micropartic...

Zinc selenide (ZnSe) doped with iron (ZnSe:Fe) has been obtained by the Bridgman method under excessive pressure of Ar. The microstructure analysis showed the sample has a homogeneous structure, which corresponds to the ZnSe:Fe solid solution. The ZnSe:Fe sample has been examined by X-band electron paramagnetic resonance (EPR) spectroscopy in the t...

The paper presents the results of a comprehensive study of yttrium gallium borate (YGa3(BO3)4) crystals low-doped (0.2 wt%) with erbium (Er3+) ions by in-situ X-ray diffraction (XRD), radioluminescence (RL), thermally stimulated luminescence (TSL) and electron paramagnetic resonance (EPR) techniques. Structural and elastic properties of YGa3(BO3)4:...

The bulk polycrystalline (pc) 3C SiC of n- and p-type obtained by thermal decomposition of methyltrichlorosilane vapor have been studied by applying the electron paramagnetic resonance (EPR), direct current (DC) conductivity, photoconductivity (PC) and PC time-resolved decay methods. The energy level of the two donor-like minority carrier traps at...

The study of structural and bulk defects in nanocrystalline samples of hydroxyapatite with a developed surface was carried out. The XRD method established distortions in the crystal lattice of the synthesized samples of hydroxyapatite (HAP), which are associated with the inclusion of impurity atoms present in the eggshell of birds used as a biologi...

Using a set of structural-spectroscopic analysis methods, the relationships between the structure, morphology, and sorption characteristics of samples of nanocrystalline carbonate-substituted calcium hydroxyapatite synthesized with the use of a biogenic source of calcium (avian eggshell) by chemical precipitation from a solution are studied. Using...

In this theses, the properties of paramagnetic centers in carbon-containing materials by continuous wave and pulse radiospectroscopy were established. In 6H, 4H, 15R polytypes of silicon carbide (SiC) of n-type the ligand structure of nitrogen (N) donors was determined. It was proposed that the N donors residing «k2» position in 6H SiC lattice and...

Applying a set of structural-spectroscopic methods of analysis we have studied the relationships between the structure, morphology and sorption characteristics of the samples of nanocrystalline carbonate-substituted hydroxyapatite (C-HAP) synthesized with the use of biogenic calcium source (poultry eggshell) obtained by the chemical deposition from...

We present the experimental and theoretical results of analysis of the optically- induced cyclotron resonance measurements carried out using the charge carriers in silicon (Si) nanostructures at 9 GHz and 4 K. Effective mass values for electrons were determined as mel∗=0.93m0 and mel∗=0.214m0 . The obtained value of the transversal mass is higher t...

The great potential of the silicon carbide (SiC) and diamond nanoparticles for future applications in spintronics initiates detailed investigation of the effects of impurities and defects in their electronic characteristics. Among impurities, nitrogen doped SiC nanoparticles are an important item to be studied, because nitrogen donors are common co...

Initial porous silicon (por-Si), carbonized porous silicon (por-Si:C), and carbon-incorporated porous silicon oxide (por-SiO2:C) layers are studied by electron paramagnetic resonance (EPR) at T = 10–13 K. Scanning transmission electron microscopy and electron energy loss (EEL) spectroscopy show that por-Si:C and por-SiO2:C layers have a highly diso...

This volume presents information about several topics in the field of electron paramagnetic resonance (EPR) study of carbon-containing nanomaterials. It introduces the reader to an array of experimental and theoretical approaches for the analysis of paramagnetic centers (dangling bonds, interface defects, vacancies, and impurities) usually observed...

In this chapter, we present the study of SiC nanoparticles obtained by pyrolysis and self-propagating high temperature synthesis (SHS) method using multiapproaches electron paramagnetic resonance (EPR) methods, including continuous wave EPR, field swept electron spin echo (FS ESE), pulsed electron nuclear double resonance (ENDOR) and four-pulse ele...

In this chapter, the nature of the defects and their relation to the incorporation of carbon, hydrogen, nitrogen and thermal treatment were investigated by electron paramagnetic resonance (EPR) spectroscopy for the fundamental insight of the electronic, optical and magnetic characteristics of the amorphous hydrogenated carbonrich silicon-carbon (a-...

We compare the magnetic and electronic configuration of single Mn atoms in molecular beam epitaxy (MBE) grown Bi2Se3 thin films, focusing on electron paramagnetic (ferromagnetic) resonance (EPR and FMR, respectively) and superconducting quantum interference device (SQUID) techniques. X-ray diffraction (XRD) and electron backscatter diffraction (EBS...

We present the first findings of the new electrically-and optically-detected magneticresonance technique (EDESR and ODMR) which reveal single point defects in the ultra-narrowsilicon quantum wells (Si-QW) confined by the superconductor δ-barriers. This techniqueallows the ESR identification without the application of the external cavity as well ast...

The diamond-like carbon (Cr-free DLC) and chromium-doped DLC (Cr doped-DLC) films prepared by a hybrid technology using a combination of pulsed laser deposition and magnetron sputtering were studied by Raman and electron paramagnetic resonance (EPR) spectroscopy. Raman spectra are dominated by the well-known carbon (D/G) band. The intensity ratio o...

Optical and magnetic properties of SiO2:C nanopowders obtained by chemical and thermal modification of fumed silica were studied by Fourier transform infrared spectroscopy, Raman, continuous wave (CW) electron paramagnetic resonance (EPR), echo-detected EPR and pulsed electron nuclear double resonance (ENDOR) spectroscopy. Two overlapping signals o...

We have studied the X-ray irradiated EuAl3(BO3)4 single crystals by means of luminescence and electron paramagnetic resonance (EPR) spectroscopy. It was found that the X-ray irradiation modifies the color of the EuAl3(BO3)4 crystal and leads to the formation of a stable Eu²⁺ centers from the Eu³⁺ centers located in a host matrix. Annealing of the c...

The temperature behavior of the electron spin resonance (ESR) spectra of nitrogen donors in n-type bulk 3C SiC monocrystals with (ND – NA) ~ 10^17 cm^(-3) was studied at T = 10-50 K. The triplet lines due to the hyperfine (hf) interaction with 14N nuclei (I = 1, 99.6%) along with a single line with the similar isotropic g values of 2.0050(3) were o...

We present the detailed study of the spin kinetics of the nitrogen (N) donor electrons in 6H SiC wafers grown by Lely method and by sublimation “sandwich method” (SSM) with a donor concentration of about 10^17 cm^-3 at T = 10-40 K. The donor electrons of the N donors substituting quasi-cubic “k1” and “k2” sites (Nk1,k2) in both types of the samples...

We have studied the temperature behavior of the electron spin resonance (ESR) spectra of nitrogen (N) donors in n-type 6H SiC crystals grown by Lely and sublimation sandwich methods (SSM) with donor concentration of 10^17 cm^-3 at T = 60-150 K. A broad signal in the ESR spectrum was observed at T > 80 K with Lorentzian lineshape and gpar = 2.0043(3...

We present the first findings of the silicon vacancy related centers identified in the non-irradiated 6H-SiC nanostructure using the electron spin resonance (ESR) and electrically-detected (ED) ESR technique. This planar 6H-SiC nanostructure represents the ultra-narrow p-type quantum well confined by the δ-barriers heavily doped with boron on the s...