Wyniki wyszukiwania - Biblioteka Nauki

1

Nanomechanical behaviour of silicon

100%

Rymuza Z. , Misiak M. , Grabiec P. , Rangelow I. , Sossna E. , Sunyk R.

Tribologia

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1999

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tom nr 3

397-409

EN

Nanomechanical chracterization of N-type, P-type single crystal silicon and polysilicon engineering, structural materials for Micro Electro Mechanical Systems (MEMS) was carried out and hardness and modulus of elasticity are given and discussed. The effect of crystal orientation ( <100> and < 111> ) on nano-scale mechanical behaviour of these materials is also considered. Comparison of nanoewar of single-crystal P-type silicon <100> and the ultra-thin coating of silicon dioxide on the same substrate is also included.

PL

Przedstawiono wyniki badań nanomechanicznych krzemu krystalicznego typu N i P oraz polikrzemu jako materiałów konstrukcyjnych dla mikrosystemów (MEMS).Podano twardość oraz moduł sprężystości.Omówiono talże wpływ orientacji krystalicznej krzemu na jego własności mechaniczne. Zamieszczono porównanie nanozużycia krzemu typu P<100> i warstwy dwutlenku krzemu na tym samym podłożu krzemowym.

2

Thermodynamic computations of the interaction coefficients between boron and phosphorus and common impurity elements in liquid silicon

80%

Dalaker H.

Computer Methods in Materials Science

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2013

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tom Vol. 13, No. 3

407--411

EN

Using the thermodynamic software FACT, and the SINTEF database for high purity silicon, the interaction coefficients between the doping elements boron and phosphorus and a range of impurity elements (Al, C, Ca, Cr, Cu, Fe, Mg, Mn, Mo, N, Na, Ni, O, Sn, Ti, V, Zn, Zr) have been calculated in liquid silicon in the temperature range 1420-1620oC. The calculations predict significant interactions between boron and phosphorus and all the evaluated elements, except between phosphorus and nitrogen, where no significant interaction was found.

PL

W pracy wykorzystano oprogramowanie termodynamiczne FACT i bazę danych SINTEF dla krzemu o wysokiej czystości do oceny oddziaływania pomiędzy zagęszczającymi pierwiastkami borem i fosforem oraz typowymi pierwiastkami (Al, C, Ca, Cr, Cu, Fe, Mg, Mn, Mo, N, Na, Ni, O, Sn, Ti, V, Zr) stanowiącymi zanieczyszczenie w ciekłym krzemie w zakresie temperatur 1420-1620oC. Wykonane obliczenia wykazały znaczne oddziaływania boru i fosforu z wszystkimi wymienionymi pierwiastkami, z wyjątkiem oddziaływania pomiędzy fosforem i azotem, którego nie zaobserwowano.

3

Magnetic properties of silicon crystals implanted with manganese

80%

Osinniy V. , Misiuk A. , Szot M. , Świątek K. , Bąk-Misiuk J. , Barcz A. , Jung W. , Prujszczyk M. , Story T.

Materials Science Poland

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2008

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tom Vol. 26, No. 3

751--757

EN

The influence of thermal treatment on magnetic properties of Si/Mn crystals grown by the Czochralski and by floating zone methods and implanted with Mn+ ions was studied by the SQUID magnetometry and electron spin resonance. Depending on thermal and hydrostatic pressure annealing conditions, three groups of Si/Mn samples were found: samples with only ferromagnetic phase, samples with ferromagnetic and paramagnetic contributions, and diamagnetic samples. The Curie temperature of ferromagnetic phase exceeds room temperature. The ESR and SQUID measurements suggest that Si/Mn implanted layer is magnetically inhomogeneous.

4

Depth Analysis of Crystalline Silicon Used for Radiation-Hard Detectors

80%

Moloi S. , McPherson M.

Acta Physica Polonica A

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2017

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tom 132

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nr 4

1387-1392

EN

Depth analysis of metal-doped crystalline silicon by the X-ray photoelectron spectroscopy technique is presented in this work. The results from this technique are used to complement those from previous techniques. The metals diffused into the silicon are gold, platinum, erbium, and niobium. In silicon, these metals induce defects that are responsible for relaxation behaviour of the material. Relaxation material is radiation-hard since the effects of radiation on devices fabricated on the material are suppressed. Considerable amounts of gold, platinum, and niobium are found in the silicon bulk. The results of this work are in good agreement with those reported earlier on the same samples using the Rutherford backscattering technique. The spectra of the natural contaminants, carbon and oxygen, are also analysed in this work.

5

First-principle calculations of effective mass of silicon crystal with vacancy defects

80%

Zhong S. , Wu M. , Lei X.

Materials Science Poland

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2016

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tom Vol. 34, No. 4

916--923

EN

The energy band structures and electron (hole) effective masses of perfect crystalline silicon and silicon with various vacancy defects are investigated by using the plane-wave pseudopotential method based on density functional theory. Our results show that the effect of monovacancy and divacancy on the energy band structure of crystalline silicon is primarily reflected in producing the gap states and the local states in valence band maximum. It also causes breaking the symmetry of energy bands resulting from the Jahn-Teller effect, while only producing the gap states for the crystalline silicon with hexavacancy ring. However, vacancy point defects could not essentially affect the effective masses that are derived from the native energy bands of crystalline silicon, except for the production of defect states. Simultaneously, the Jahn-Teller distortions only affect the gap states and the local states in valence band maximum, but do not change the symmetry of conduction band minimum and the nonlocal states in valence band maximum, thus the symmetry of the effective masses. In addition, we study the electron (hole) effective masses for the gap states and the local states in valence band maximum.

6

Silicon behaviour at the blast furnace process

80%

Klimczyk A. , Stachura R. , Bernasowski M. , Łędzki A.

Journal of Achievements in Materials and Manufacturing Engineering

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2012

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tom Vol. 55, nr 2

712--715

EN

Purpose: Views on the reduction of SiO2 at the blast furnace process began to change in the mid 70s. Nowadays it is claimed that the silicon appears in the metal not only from the slag SiO2 reduction at the liquid phase, but also from a gaseous SiO. Presented in this paper, laboratory tests were aimed on finding the effect of temperature and MgO containing in the slag on the dynamics of the Si transition to the pig iron at the liquid phase at time when slag lies on metal. Design/methodology/approach: Laboratory tests carried out in laboratory on devices AGH described in detail in other studies such as [8-11]. Metal used in the study obtained by carbonizing the carbon-iron saturation assuming the values given by J. Chipman [7]. Findings: Observations of industrial units in combination with laboratory tests allowed us to approximately determine the contribution of silicon from the gaseous SiO in hot metal. Research limitations/implications: Si content in the metal after the test at a constant temperature is less than taping pig iron of about 0.15 to 0.35%. This means that in addition to the reduction reaction of the silica source of silicon in the slag is reduced gaseous SiO , which is in line with those of the authors [2-5, 8-10]. This will also be the subject of the next stage of research. Practical implications: As a result, developed guidelines and proposals for the conduct of blast-furnace technology to minimize Si in pig iron. Originality/value: The AGH research team has approached to issue of SiO2 reduction complexly. The work is divided into stages. Laboratory studies combined with industry specific observations. As a result of this approach to work is possible to develop a practical technology to minimize silicon in the pig iron. Articles published in reputable journals on similar or related topics do not include all issues.

7

Formation of silicon oxide nanowires in nanomaterial synthesis experiments based on the usage of tube furnace

80%

Li C. , Solomon V. , Moro M. , Welsh C. , Mccauley T. , Bauer M. , Cupo J.

Materials Science Poland

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2013

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tom Vol. 31, No. 3

350--356

EN

In an effort to synthesize doped ZnO nanowires, SiOx nanowires were obtained accidently. In the experiment, mixed powders containing chemicals such as ZnO, graphite, Ga2O3, and In2O3 were placed in the center of a tube furnace, where the temperature was set to 1200 °C and the vacuum was approximately 27 Pa. Silicon wafers were placed around the vicinity of the furnace exit to collect the expected nanomaterials. After prolonged heating, grey layers were found on top of one wafer located inside the furnace. The layer showed no adhesion to the substrate. Characterization by using Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM), and Energy Dispersive X-ray Spectroscopy (EDS) revealed that this layer consisted of SiOx nanowires. Formation of Si-containing liquid drop and the subsequent growth of SiOx nanowires out of it are suggested as the growth mechanism.

8

Stress degradation of Ta2O5 films on silicon

80%

Novkovski N. , Atanassova E.

Prace Naukowe Instytutu Podstaw Elektrotechniki i Elektrotechnologii Politechniki Wrocławskiej. Konferencje

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2004

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tom Vol. 40, nr 15

16-19

EN

Degradation of interface and film properties during constant voltage and constant current stress of Ta2O5 films grown on silicon was studied. It was shown that the degradation consists of positive and negative charge trapping and thinning of the extremely thin silicon dioxide created between the Ta2O5 and the silicon substrate.

9

SiN/SiO2 passivation stack of n-type silicon surface

80%

El Amrani A. , Si-Kaddour R. , Maoudj M. , Nasraoui C.

Materials Science Poland

|

2019

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tom Vol. 37, No. 3

482--487

EN

The SiN/SiO2 stack is widely used to passivate the surface of n-type monocrystalline silicon solar cells. In this work, we have undertaken a study to compare the stack layer obtained with SiO2 grown by both rapid thermal and chemical ways to passivate n-type monocrystalline silicon surface. By varying the plateau time and the plateau temperature of the rapid thermal oxidation, we determined the parameters to grow 10 nm thick oxide. Two-step nitric acid oxidation was used to grow 2 nm thick silicon oxide. Silicon nitride films with three refractive indices were used to produce the SiN/SiO2 stack. Regarding this parameter, the minority carrier lifetime measured by means of QSSPC revealed that the refractive index of 1.9 ensured the best passivation quality of silicon wafer surface. We also found that stacks with nitric acid oxidation showed definitely the best passivation quality. In addition to produce the most efficient passivation, this technique has the lowest thermal budget.

10

Influence of Silicon and Cobalt Laser Alloying on the Microstructure and Nanomechanical Properties of the Gray Cast Iron Surface Layer

80%

Paczkowska M.

Journal of Research and Applications in Agricultural Engineering

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2022

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tom Vol. 67, nr 2

13--19

EN

The aim of the research was to modify the surface layer of flakc iron by laser alloying with composition of elements: Si and Co and the evaluation of the obtained effects (regarding the changes in the surface layer microstructure and its chosen properties). In the first part, the treatment consist on covering the cast iron surface with the alloying composition layer, and in the second part – heating of this surface with laser beam using molecutar laser. The treatment effects were estimated with: SEM, EDS, hardness tester, nanoindentalion tester and surface profile device. Il was started (among others), that the alloyed zone in the surface layer flake iron after performed laser treatment was gained and it was characterized by following features (in comparison to the core material): fine and homogencous microstructure with some similarities to the hardened white cast iron, presence of Co and increased amount of Si. lt was noticed that such properties as hardness and Young's modulus have been increased.

11

Mechanically Stimulated Changes in Surface Electrical Conductivity of X-Irradiated Silicon Crystals

80%

Lys R. , Żyłka M. , Shykorjak J. , Slobodzyan D. , Żyłka W. , Pavlyk B.

Advances in Science and Technology. Research Journal

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2023

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tom Vol. 17, no 2

226--231

EN

Changes in the resistance of single crystals of p-type conductivity silicon under the action of mechanical loading were investigated in this research. Also, non-irradiated and pre-irradiated X-rays experimental samples were studied. It was found that at small deformation values when they are at the initial stage of the action of elastic deformation, a section forms and increases, on which the resistance practically does not depend on the applied mechanical load. In irradiated crystals, at small deformation values, electron generation processes dominate, which then recombine with the main carriers – holes. The consequence of such processes is the appearance of a maximum increase in electrical resistance at the initial stage of elastic deformation of experimental samples irradiated with X-rays. Charge carrier generation processes begin to dominate with further deformation. Such processes occur as a result of the release of acceptor centers from other complex defects, which are destroyed during the deformation of the Si crystal and captured by mobile dislocations. Thus, the processes of generation of charge carriers prevail over the processes of gettering and, accordingly, a mechano-stimulated decrease in the electrical resistance of p-Si samples occurs.

12

Design and simulation of single-electrode liquid crystal phased arrays

80%

Bellini B. , Geday M. A. , Bennis N. , Spadło A. , Quintana X. , Otón J. M. , Dąbrowski R.

Opto-Electronics Review

|

2006

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tom Vol. 14, No. 4

269-273

EN

Liquid crystal (LC) phased arrays and gratings have been employed in optical switching and routing [1]. These diffractive optic elements are of great interest because they can be scaled up to a large number of elements and their optical properties can be electrically addressed with a low driving voltage. LC phase gratings have been achieved either by periodic addressing of pixels or by using periodically-modified structures. The latter approach leads to less reconfigurable devices but the addressing is simpler. In this paper we focus on optical phased arrays where the phase is varied either continuously or discretely and where the periodicity is induced by electrode configuration. We first describe a possible structure based on a conductive silicon wafer. We argue that this structure can induce either continuously or discretely varying arrays while applying single voltage to the array. In the second part we simulate the behaviour of such arrays. We base the simulation on a LC synthesized at the Military University of Technology, this high-birefringence nematic LC shows in a 4-µm thick cell a linear phase shift range of more than 3600 between 1.2 V and 1.8 V. We calculate the distribution of the LC molecule director and assess the performance of the array with respect to the applied voltage. Finally, the relevance of such technology for switchable phased arrays is discussed.

13

Lawina ngród za krzemowe fotodiody lawinowe

80%

Węgrzecka I.

Elektronika : konstrukcje, technologie, zastosowania

|

1998

|

tom Vol. 39, nr 7-8

3-4

14

Integrated instruments for total chemical analysis

80%

Dziuban J.

Materiały Elektroniczne

|

2001

|

tom T. 29, nr 1-2

70-71

EN

Previous works on silicon micromachined devices started in the Institute of Microsystems Technology (ITM) of the Wroclaw University of TEchnology (WUT) in late 80's, although some fundamental technological works on silicon anisotropic etching for three-dimensional structures fabrication were done in mid 70's. Our Institute was the first in Poland recognising a need of micromachined sensors and actuators investigations. In the lecture some of the most interesting past works will be shown. Newly developed components for analytical chemistry and microchemistry will be presented. a short sketch of recently discovered fast deep anistropic etching of single silicon wafers and other materials will be presented. Samples of devices and short TV movie on our works will be shown.

15

Impact of Carbon Nanotubes on the Mechanical and Electrical Properties of Silicone

80%

Sałaciński M. , Dydek K. , Leski A. , Kozera R. , Mucha M. , Karczmarz W.

Fatigue of Aircraft Structures

|

2022

|

tom Iss. 14

135--153

EN

This paper presents the results of a structure study of a dispersion composite on a silicone matrix with a filler in the form of multi-walled carbon nanotubes (MWCNTs). The study aims to determine the effect of the filler on the composite mechanical properties and electrical conductivity. Materials that are electrically conductive and exhibit high mechanical properties can find applications in high-strain sensors. During the study, the characteristic properties of the susceptible materials, silicone alone and silicone with different filler contents (4%, 6%, and 8% by weight), were determined after curing. Microscopic observations were performed to assess the influence of carbon fillers on the material structure and to determine the level of homogeneity of the material. Examination of mechanical properties facilitated the determination of the Shor A hardness (ShA), stiffness, and Poisson’s ratio of the cured composites, depending on the nanotubes’ content. In parallel with the study of mechanical properties, the effect of loading, and the associated deformation of the samples, on the conductivity of the composite was investigated. Based on the results obtained, a discussion was carried out on the type of conductivity characteristic of silicone with different filler content as well as depending on the level of deformation of the samples.

16

Ab initio calculations of the 29Si NMR chemical shifts of simple silicon compounds

80%

Cypryk M.

Bulletin of the Polish Academy of Sciences. Chemistry

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1999

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tom Vol. 47, No. 1

33-40

EN

Two methods of (29) Si NMR calculations, GIAO-HF and GIAO-B3LYP /6-311+G(2d,p) were compared for a series of simple silicon compounds. The (29) Si isotropic chemical shifts obtained by both methods are in reasonable agreement with the experi-ment, although the GIAO-HF method predicts the chemical shifts slightly more precisely. The accuracy is generally worse than that reported for (13)C chemical shifts calculations.

17

Silicon TCD for the methane and carbon monoxide detection

80%

Łysko J. M. , Latecki B. , Nikodem M. , Górska M. , Mróz J. , Małachowski M.

Journal of Telecommunications and Information Technology

|

2005

|

tom nr 1

94-97

EN

Analytical model, design principles, technology and test results concerning a thermal conductivity detector (TCD) are presented. Prototype TCD units fabricated using the standard silicon IC VLSI and MEMS techniques are reported. The detectors are integrated with gas separation columns and micro-valve dosing systems. Initial tests were carried out in a gas mixture containing methane, carbon monoxide, oxygen, hydrogen and nitrogen.

18

Silikony w budownictwie

80%

Sawicki J.

Izolacje

|

2005

|

tom R. 10, nr 7-8

41--45

PL

Na rynku budowlanym stale powiększa się liczba wyrobów opartych na silikonach. Wynika to z ich szczególnych właściwości fizykochemicznych, nadających pożądane cechy uzytkowe i gwarantujących spełnianie wymogów niemozliwych do osiągnięcia przy zastosowaniu innych środków.

19

Determination of the photodynamic activity of porphyrins: Potential photosensitizers for treatment of age-related macular degeneration

80%

Neri C. R. , Maestrin Prado A. P. J. , Ribeiro A. O. , Serra O. A. , Iamamoto Y.

Materials Science

|

2002

|

tom Vol. 20, No. 2

97-103

EN

Age-related macular degeneration (AMD) is the leading cause of irreversible visual loss in people between 65 and 74 years. Recently, the photodynamic therapy (PDT) is used as experimental treatment for exudative AMD. In a PDT process, a reaction takes place when a photosensitiser (PS), light of appropriated wavelength, and oxygen are present at the same time. In general, the PS are porphyrins and related systems. The aim of this study was to evaluate the photodynamic activity (PA) of the Benzoporphyrin (BPH2), Protophorphyrin-IX (Proto), Tetrakis(phydroxyphenyl) porphyrin (THPPH2) and Tetrakis(2-hydroxy-5-nitrophenyl)porphyrin (T2H5NPPH2). The PA is related to quantum yields (??) for the singlet oxygen (1O2.) production. Uric acid, a known singlet oxygen scavenger, is utilised as a chemical dosimeter in the PDT. When the uric acid (UA) and PS solution is irradiated with laser light the UA band absorbance at 293 nm decreases as a rapid evaluation of relative PA of the PS.

20

Preparation and properties of colloidal nanosize silica dioxide for polishing of monocrystalline silicon wafers

80%

Gaishun V. E. , Tulenkova O. I. , Melnichenko I. M. , Baryshnin S. A. , Potapenok Y. A. , Xlebokazov A. P. , Stręk W.

Materials Science

|

2002

|

tom Vol. 20, No. 2

19-22

EN

Colloidal silica can be used for final general metallographic polishing. It is used to polish single crystal silicon for electronic applications and, subsequently, polycrystalline silicon for solar cells, gallium arsenide, indium phosphide, titanium, gadolinium gallium garnet and sapphire. The silica dioxide are dispersed in water with alkaline compound added to obtain the desired pH.