Nadiia Safriuk

Nadiia Safriuk
National Academy of Sciences of Ukraine | ISP · V. E. Lashkaryov Institute of Semiconductor Physics

Candidate of Sciences (PhD)

About

41
Publications
13,580
Reads
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195
Citations
Citations since 2016
13 Research Items
142 Citations
201620172018201920202021202205101520
201620172018201920202021202205101520
201620172018201920202021202205101520
201620172018201920202021202205101520
Additional affiliations
November 2008 - present
National Academy of Sciences of Ukraine
Position
  • Senior Researcher
Education
September 2000 - June 2005
Chernivtsi National University
Field of study
  • solid state

Publications

Publications (41)
Article
Full-text available
The morphology and microstructure of the Pb1−xSnxTe surfaces polished by the H2O2–HBr–ethylene glycol etchants have been investigated using atomic force and electron microscopy techniques. Treatment of the Pb0.8Sn0.2Te crystal surfaces with new etchant mixtures allows to obtain ultra-smooth surfaces Ra < 1 nm. The single crystal surfaces after chem...
Article
Full-text available
We report about a study of the formation and current transport mechanism of ohmic contacts to n +-InN with electron concentrations of 2 × 10 18 , 8 × 10 18 , and 4 × 10 19 cm −3. Pd/Ti/Au ohmic contacts are formed by the proposed approach of simultaneous magnetron metal de-position and in-situ temperature annealing, which allows obtaining a low con...
Article
Full-text available
The temperature dependences of contact resistivity are measured for Pd/Ti/Au ohmic contacts toward indium nitride (with different doping level 2.0ċ1018 and 8.3ċ1018 cm-3) over the wide temperature range (4.2 - 380 K). The growing curves are obtained in the entire investigated temperature range for both doping level. They are explained within the me...
Article
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Review of original results concerning electrochemical formation of porous Si layers and investigation of properties inherent to the formed layers has been presented. The results related with observation of changes in pores’ morphology depending on the etching conditions, correlation of morphology of the porous layers with their surface composition,...
Article
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A new method to prepare vanadium oxide with a high temperature coefficient of resistance (TCR) and low resistance for uncooled micro-bolometers has been proposed. Amorphous vanadium oxide films with V2O3 phase inclusions have been fabricated on silicon and silica substrates at the temperature 200 °C by using the direct current reactive magnetron spu...
Article
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This paper describes the in-situ synthesis in polymer films of the nanocrystals (NCs) of the ternary semiconductors Cd1-xCuxS and Cd1-xZnxS as well as the results of investigations of their structure and optical properties. It has been established that, in case of Cd1-xCuxS in a large range of Cu to Cd ratios, the hexagonal structure is dominating...
Conference Paper
Full-text available
Development of ohmic contacts to InN films is promising for a future technology of gigahertz electronics and modern high-electron-mobility transistors. From the other side, high precision measurement of ohmic contact resistivity is a main demand for a quality and reliability control. However, InN has high density of structural defects, due to growi...
Article
Full-text available
The Au and por-Au films obtained by pulsed-laser deposition are characterizedby X-ray reflectometry and diffractometry. The main structural parameters (density (porosity), thickness, surface roughness) are obtained. As shown, the additional measurements of the latticeparameter allow more correctly determine the porosity value of the Au films.
Article
Full-text available
Superlattices (SLs) consisting of symmetric layers of GaN and AlN have been investigated. Detailed X-ray diffraction and reflectivity measurements demonstrate that the relaxation of built-up strain in the films generally increases with an increasing number of repetitions; however, an apparent relaxation for subcritical thickness SLs is explained th...
Article
The influence of strain and barrier/well thickness ratio on recombination processes in multi-quantum well (MQW) Al0.1Ga0.9N/GaN structures was investigated using X-ray diffraction and Raman and photoluminescence spectroscopies. The deformation state of the wells and barriers was determined. In addition, the value of the polarization fields, the den...
Article
Full-text available
A comprehensive study of structural and photoluminescent properties of single crystals of CdTe:V samples has been made. Single crystal ingots were grown using the vertical Bridgman method with a temperature gradient of 25◦ C/cm. An estimated concentration of vanadium impurity in the melt was 1019cm−3 . Free carrier concentration was (4 − 7) × 106cm...
Article
Full-text available
Presented in this paper are experimental data on structural properties of contact metallization and temperature dependence of the specific contact resistance for ohmic contacts Au–Ti–Pd–n+-InP and Au–Ti–Ge–Pd-n+-InP prepared using the method of successive thermal evaporation of metals in oil-free vacuum in one process cycle onto the n+-n-n++-n+++-I...
Article
Full-text available
The Au and por-Au films obtained by pulsed-laser deposition are characterizedby X-ray reflectometry and diffractometry. The main structural parameters (density (porosity), thickness, surface roughness) are obtained. As shown, the additional measurements of the latticeparameter allow more correctly determine the porosity value of the Au films.
Article
The structural and optical properties of the Ge1-xSnx layers with Sn mole fraction x of about 0.04 and 0.07 grown by molecular beam epitaxy on strain relaxed (001) Ge buffer layers have been investigated. The formation of GeSn solid solutions is proved by the high-resolution X-ray diffraction and micro-Raman investigations. The Ge1-xSnx layers are...
Conference Paper
Full-text available
The structural properties of high-doped n-InN heteroepitaxial films and Au-Ti-Pd-InN ohmic contacts were analysed. The mosaic structure of the InN films was shown by X-ray diffraction. The level of screw dislocations exceed 108 cm-2 , the level of edge dislocations exceed 109 cm-2 . It was found, that enrichment of InN films by indium leads to the...
Article
Full-text available
The temperature dependences of the contact resistivity (ρc) of ohmic contacts based on the Au–Ti–Pd–InN system are measured at an InN doping level of 2 × 1018 cm–3 in the temperature range of 4.2–300 K. At temperatures T > 150 K, linearly increasing dependences ρc(T) are obtained. The dependences are explained within the mechanism of thermionic cur...
Article
The temperature dependences of the contact resistivity (ρc ) of ohmic contacts based on the Au-Ti-Pd-InN system are measured at an InN doping level of 2 × 1018 cm−3 in the temperature range of 4.2–300 K. At temperatures T > 150 K, linearly increasing dependences ρc (T) are obtained. The dependences are explained within the mechanism of thermionic c...
Article
The temperature dependences of the contact resistivity (ρ c ) of ohmic contacts based on the Au-Ti-Pd-InN system are measured at an InN doping level of 2 × 1018 cm−3 in the temperature range of 4.2–300 K. At temperatures T > 150 K, linearly increasing dependences ρ c (T) are obtained. The dependences are explained within the mechanism of thermionic...
Article
Full-text available
Experimental data on manufacturing the ohmic contacts Au–Ti–Pd–n+-InP, formed using vacuum deposition of metal onto a heated to 300 °C substrate representing an epitaxial n+-n-n++-n+++-InP structure. The specific contact resistance measured at room temperature was about 7∙10–5 Ohm∙cm2. Voltage-current characteristics within the temperature range 11...
Chapter
Full-text available
Основным направлением данного исследования является изучение дефектной структуры и упруго-деформированного состояния наноструктур, в том числе, с квантовыми точками и массивами квантовых точек. Широко распространенной причиной брака полупроводниковых матриц обычно является возникновение в них на том или ином этапе изготовления или обработки поверхн...
Article
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In this work, the influence of micro- and macro-deformation profiles in GaN nanowires (NWs) on the angular intensity distribution of X-ray diffraction are studied theoretically. The calculations are performed by using kinematical theory of X-ray diffraction and assuming the deformation decays exponentially from the NW/substrate interface. Theoretic...
Article
Full-text available
Dependence of deformation characteristics changing in superlattice (SL) structures AlxGa1-xN/GaN with Al (-10%) on the well-barrier thickness ratio in period was studied in this work. The deformation state of SL and individual layers, relaxation level and periods, layers thickness and composition of AlxGa1-xN layers were analyzed using high-resolut...
Article
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The characteristics of a damaged layer of p-Cdx Hg1 − x Te/CdZnTe (x ∼ 0.223) heterostructures after implantation by 100-keV silver ions with the implantation dose Q = 3.0 × 1013 cm−2 have been obtained using X-ray diffraction, atomic force microscopy, and electron microscopy. It has been found that, as a result of the ion implantation and subseque...
Article
Full-text available
Methodical approaches to the analysis of X-ray data for GaN films grown on different buffer layers and different substrates are presented in this article. Possibilities of using the different methods of dislocation structure investigation were analyzed and approaches for evaluation of deformation level and relaxation are discussed. Clarity and accu...
Article
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We present a comparative study of the strain relaxation of GaN/AlN short-period superlattices (SLs) grown on two different III-nitride substrates introducing different amounts of compensating strain into the films. We grow by plasma-assisted molecular beam epitaxy (0001)-oriented SLs on a GaN buffer deposited on GaN(thick)-on-sapphire template and...
Article
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The methods of high-resolution X-ray diffraction have been used to study the multilayered structures in an In x Ga1 − x N/GaN system grown by the method of metal-organic chemical-vapor deposition. A correlation between the strain state (relaxation) of the system, the indium content within quantum wells, the ratio of the barrier/well thicknesses, an...
Article
Full-text available
The methods of high-resolution X-ray diffraction have been used to study the multilayered structures in an InxGa1–xN/GaN system grown by the method of metal–organic chemical-vapor deposition. A correlation between the strain state (relaxation) of the system, the indium content within quantum wells, the ratio of the barrier/well thicknesses, and the...
Article
Full-text available
The influence of template type and residual strain of the buffer layer on the structural properties of GaN/AlN superlattices (SLs) was studied using high resolution x-ray diffraction. Using sapphire substrates, an effective thinning of the GaN quantum wells and the corresponding thickening of the AlN barriers were observed in SL structures grown on...
Article
Full-text available
High resolution X-ray diffractometry (HRXRD) was used to investigate InxGa1−xN/GaN multilayered structures grown by the metal-organic chemical vapor deposition (MOCVD) method. Deformation conditions in the superlattice (SL) and its separate layers, degree of relaxation in the structure layers, as well as the period of the SL, thicknesses of its lay...
Article
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High-resolution X-ray diffraction analysis and scanning confocal Raman spectroscopy are used to study the spatial distribution of strains in the InxGa1–xN/GaN layers and structural quality of these layers in a multilayered light-emitting diode structure produced by metal–organic chemical vapor deposition onto (0001)-oriented sapphire substrates. It...
Article
Full-text available
The results of high resolution X-ray diffractometry (HRXD) studies of the structural properties of AlGaN/GaN/(0001)Al2O3 heterosystems are reported. The microscopic nature of spatial heterogeneities (microdeformations and the dislocation density) in those structures is discussed on the basis of the results obtained. The gradient distribution of dis...
Article
Full-text available
The structural properties of AlGaN/GaN heterostructures grown by metal organic chemical vapor deposition on sapphire substrates with different thicknesses were studied by high-resolution x-ray diffraction. The relation between the deformations and dislocation densities in the layer and substrate was established. The dependence of the system’s curva...

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