Wyniki wyszukiwania - BazTech

1

Novel transient-state analysis approach for distributed temperature sensing based on spontaneous Raman scattering

Shatarah Iyad S. M., Olbrycht Robert, Więcek Bogusław

Opto-Electronics Review

|

2024

|

Vol. 32, No. 2

art. no. e150605

EN

The light scattering phenomenon in optical fibres has been implemented in several applications for years. Nowadays, commercial distributed sensing systems for temperature measurements - distributed temperature sensing (DTS) - are gaining more attention and are being applied in many fields. The DTS systems are commonly based on optical time domain reflectometry or optical frequency domain reflectometry analysis approaches. This paper presents the simulation model and primary experimental results of a novel approach for data analysis for DTS systems based on the measurement of the backscattered Raman anti-Stokes radiation: the optical transient-state domain reflectometry. The novelty of this approach is the fast and accurate proposed analysis algorithm, as well as the cost-effective, secure and reliable set-up, whose main aspect is the implementation of long, low-power input laser pulses.

2

Tuning the localized surface plasmon resonance of "core-shell Ag nanoparticles on dielectric substrates" to near-infrared window: applications to surface-enhanced Raman spectroscopy

Salimian Sina, Soofi Hadi

Optica Applicata

|

2020

|

Vol. 50, nr 3

343--355

EN

In this article, plasmonic characteristics of SiO2-Ag and hollow core Ag nanoparticles placed on dielectric substrates are investigated and tuned to the NIR wavelength spectrum for biological applications. It is shown that by placing the core-shell Ag nanoparticles on a dielectric substrate and exciting the normal plasmon mode of the nanoparticle, it is possible to obtain strong plasmon resonances at wavelengths as long as λ = 700 nm which exhibits a red shift of more than 300 nm compared to the resonance of freestanding pure Ag nanoparticles at which normal plasmon resonance wavelength shows a sensitivity of approximately 100 nm/RIU in respect to the substrate refractive index change. “SiO2-Ag and hollow core Ag nanoparticles on silicon” are optimized to exhibit a strong normal plasmon resonance at λ = 633 nm while preserving the plasmonic field enhancement intact. Finally, a three dimensional substrate for surface-enhanced Raman spectroscopy (SERS) is designed and numerically investigated. The substrate is composed of Si nanorod array decorated with the designed nanoparticles which exhibits superior characteristics such as a uniform and gapless field enhancement and an electromagnetic enhancement factor of more than 3 × 106, an order of magnitude higher than the enhancement factor for a similar structure decorated with Au nanoparticles.

3

Thermoluminescence properties of undoped diamond films deposited using HF CVD technique

Paprocki K., Winiecki J., Kabacińska R., Przegiętka K., Szybowicz M., Fabisiak K.

Materials Science Poland

|

2017

|

Vol. 35, No. 4

785--790

EN

Natural diamond has been considered as a perspective material for clinical radiation dosimetry due to its tissue biocompatibility and chemical inertness. However, the use of natural diamond in radiation dosimetry has been halted by the high market price. The recent progress in the development of CVD techniques for diamond synthesis, offering the capability of growing high quality diamond layers, has renewed the interest in using this material in radiation dosimeters having small geometrical sizes. Polycrystalline CVD diamond films have been proposed as detectors and dosimeters of β and α radiation with prospective applications in high-energy photon dosimetry. In this work, we present a study on the TL properties of undoped diamond film samples grown by the hot filament CVD (HF CVD) method and exposed to β and α radiation. The glow curves for both types of radiation show similar character and can be decomposed into three components. The dominant TL peaks are centered at around 610 K and exhibit activation energy of the order of 0.90 eV.

4

Annealing and Ni content effects on EPR and structural properties of Zn1–xNixO aerogel nanoparticles

Sayari A., El Mir L.

Materials Science Poland

|

2017

|

Vol. 35, No. 3

454--462

EN

Zn1–xNixO aerogel nanopowders with nickel concentration in the range of 0.05 ≤ x ≤ 0.25, were synthesized by the sol-gel processing technique and post-annealed in air at 500 ˚C. Structural, vibrational, thermal and magnetic properties of the as-prepared and annealed Zn1–xNixO powdered samples were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), Raman scattering, thermal gravimetric analysis (TGA) and electron paramagnetic resonance (EPR) spectroscopy. In addition to the ZnNiO phase, XRD analysis revealed the formation of a secondary NiO phase when the Ni content was greater than or equal to 10 %. The TEM images confirm that the particle size is in the range of 20 nm to 40 nm, in accordance with XRD results, and the particles are well dispersed. Raman scattering measurements confirm the wurtzite structure of the synthesized Zn1–xNixO nanopowders and show that intrinsic host-lattice defects are activated when Ni2+ ions are substituted to the Zn sites. Room temperature ferromagnetic order was observed in all of the samples and was strongly dependent on the Ni content and thermal annealing. These results indicate that the observed room temperature ferromagnetism in ZnNiO may be attributed to the substitutional incorporation of Ni at Zn sites.

5

The features of flame temperature measurement

Herasymenko V., Seheda O., Stadnyk B.

Zeszyty Naukowe Politechniki Rzeszowskiej. Elektrotechnika

|

2015

|

z. 34 [292], nr 3

81--85

EN

The flame temperature measurement gives the understanding of combustion processes and is important for the temperature control systems. In this paper the review and analyze of the methods of flame temperature measurement are represented. Each of them is effective under certain condition. Nowadays the method of Raman-scattering is promising in this field. It pretends to avoid some of the errors in other existing techniques.

PL

Pomiar temperatury płomienia pozwala zrozumieć procesy spalania i jest ważnym dla systemów kontroli temperatury. W artykule przedstawiona jest analiza metod pomiaru temperatury płomienia. Każda z nich jest skuteczna przy spełnieniu pewnych warunków. W tej dziedzinie metoda rozpraszania ramanowskiego jest obecnie obiecująca. Wspomniana metoda pozwala uniknąć niektórych błędów charakterystycznych dla innych technik.

6

Influence of aluminium concentration in Zn0:9V0:1O nanoparticles on structural and optical properties

Sayari A., El-Mir L., Al-Heniti S., Al-Harbi T., Yaghmour S. J., Al-Ghamdi A. A.

Materials Science Poland

|

2015

|

Vol. 33, No. 1

198--204

EN

The (V,Al) co-doped ZnO nano-structured powders (Zn0.9V0.1AlxO, where x = 0.02, 0.03 and 0.04) were synthesized via the sol-gel technique and their structural and optical properties were investigated. The effect of Al concentration on the structural and optical properties of the Zn0.9-xV0.1AlxO nanopowders was studied using various techniques. The XRD patterns indicate that the samples have a polycrystalline wurtzite structure. The crystallite size increases with increasing the Al content and lies in the range of 23 to 30 nm. The lattice strain, estimated by the Stokes-Wilson equation, decreases when Al content increases. SEM and TEM micrographs show that Zn0.9-xV0.1AlxO powders are the agglomeration of nanoparticles having spherical and hexagonal shapes with dimensions ranging from 20 to 30 nm. FT-IR spectra show a distinct absorption peak at about 500 cm-1 for ZnO stretching modes and other peaks related to OH and H2O bands. Raman spectra confirm the wurtzite structure of the Zn0.9-xV0.1AlxO nanoparticles. The direct band gaps of the synthesized Zn0.9-xV0.1AlxO nanopowders, estimated from the Brus equation and the crystallite sizes deduced from XRD, are around 3.308 eV. The decomposition process of the dried gel system was investigated by thermal gravimetric analysis (TGA).

7

Proces fotopolimeryzacji mieszanin akrylan/nanokrzemionka : badany metodami spektroskopii rozproszeniowej

Nowicka A., Ziobrowski P., Szybowicz M., Sądej-Bajerlein M., Andrzejewska E., Drozdowski M.

Przetwórstwo Tworzyw

|

2012

|

[R.] 18, nr 5

485-488

PL

W niniejszej pracy przedstawiono wyniki badań procesu polimeryzacji inicjowanej promieniowaniem UV mieszaniny akrylanu 2-hydroxyetylu (HEA) zawierającego zdyspergowany nanonapełniacz w postaci hydrofobizowanej krzemionki Aerosil ® R7200. W badaniach wykorzystano metody spektroskopii rozproszeniowej: Brillouina i Ramana. Spektroskopia Brillouiona pozwoliła na określenie zmian właściwości sprężystych w trakcie procesu polimeryzacji dla różnej zawartości krzemionki (nanonapełniacza). Spektroskopia Ramana pozwoliła na monitorowanie procesu fotopolimeryzacji badanych układów. Została ona również wykorzystana do zbadania wpływu tlenu na proces polimeryzacji.

EN

This paper presents the results of the investigation of UV-initiated polymerization of 2-hydroxyetyl acrylate (HEA) containing a nanofiller (modified hydrophilic silica Aerosil ® R7200). The study was performed using scattering spectroscopy methods. Brillouin spectroscopy has been used to estimate changes in elastic properties occurring during the photopolymerization process of formulation containing different nanosilica contents. Raman scattering method was used to follow the photopolymerization process and to study the oxygen effect.

8

Badania strukturalne warstw węglowych w kontaktach omowych : porównanie widm ramanowskich obserwowanych od strony warstwy krzemkowej oraz podłoża z węglika krzemu

Borowicz P., Adamus Z., Ekielski M., Piotrowska A., Kuchuk A., Borysiewicz M., Kamińska E., Latek M.

Elektronika : konstrukcje, technologie, zastosowania

|

2012

|

Vol. 53, nr 9

31-34

PL

Trzy próbki węglika krzemu o politypie 4H (4H-SiC) pokryto sekwencją warstw węgiel/nikiel/krzem/nikiel/krzem, a następnie poddano wygrzewaniu w celu wytworzenia kontaktów omowych. Analiza pasm ramanowskich wskazuje na różnice pomiędzy widzianą z obu stron strukturą warstwy węglowej pomimo, że grubość samej warstwy węglowej odpowiada 8 do 10 monowarstwom grafenowym.

EN

The structure of carbonic layer in three samples composed of 4H polytype of silicon carbide covered with the following sequence of layers: carbon/ nickel/silicon/nickel/silicon was investigated with Raman spectroscopy. Different thermal treatment of the samples lead up to differences in the structure of carbonic layer. Raman measurements with excitation focused on two interfaces: silicon carbide/carbon and carbon/silicide show differences in the structure of carbonic film at both sides although its thickness corresponds to 8 + 10 graphene layers.

9

Raman Polarization Pulling and Amplification for Polarization Division Multiplexing Transmission System

Perlicki K.

International Journal of Electronics and Telecommunications

|

2011

|

Vol. 57, No. 4

519-522

EN

The numerical modelling of the Raman polarization attraction and amplification process in the telecommunication band around 1550 nm is presented. The possibility of achieving both polarization pulling and amplification in Polarization Division Multiplexing transmission system by exploiting the polarization dependence of stimulated Raman scattering is investigated. The acceptable crosstalk for the Polarization Division Multiplexing transmission systems was achieved for some attraction/amplification block parameters.

10

Badania strukturalne warstw węglowych w niklowych kontaktach omowych za pomocą widzialnej i nadfioletowej spektroskopii ramanowskiej

Borowicz P., Kuchuk A., Adamus Z., Borysiewicz M., Ekielski M., Kamińska E., Piotrowska A., Latek M.

Elektronika : konstrukcje, technologie, zastosowania

|

2011

|

Vol. 52, nr 9

103-106

PL

Trzy próbki węglika krzemu o politypie 4H (4H-SIC) pokryte następującą sekwencją warstw węgiel/nikiel/krzem/nikiel/krzem były badane za pomocą spektroskopii ramanowskiej wykorzystującej widzialne, jak również nadfioletowe wzbudzenie. Różne warunki obróbki termicznej powodują zmiany w strukturze warstwy węglowej. Badania ramanowskie skoncentrowano w zakresie przesunięcia Ramana pomiędzy 1000 cm⁻¹ a 2000 cm⁻¹, ponieważ w tym zakresie leżą najważniejsze pasma węglowe historycznie oznaczone jako G oraz D. Analiza kształtu i położenia tych pasm oraz iloraz natężeń umożliwia określenie stopnia grafityzacji warstwy węglowej Zastosowanie wzbudzenia w nadfioletowym zakresie spektralnym umożliwia analizę struktury warstwy węglowej, która tworzy się na powierzchni swobodnej krzemku niklu.

EN

Three samples of 4H polytype of silicon carbide (4H-SiC) covered with following sequence of layers. carbon/nickel/silicon/nickel/silicon were investigated with visible (VIS) and ultraviolet (UV) micro-Raman spectroscopy Different thermal treatment of each sample result in differences of structure of carbonic layer. The range of Raman shift placed between 1000 cm⁻¹ and 2000 cm⁻¹ was taken into account because the main carbonic bands D and G are placed in this region. Analysis of the positions of these bands and their intensity ratio obtained from VIS excitation makes possible to estimate the graphitization of the carbonic layer. Application of UV excitation allowed us to analyze the carbonic layer built on the free surface of silicide layer.

11

Raman scattering of ZnO films prepared by the laser molecular beam epitaxy

Wang C., Chen Z., He Y., Li L., Zhang D.

Materials Science Poland

|

2010

|

Vol. 28, No. 1

153--161

EN

A series of ZnO films have been prepared on Si (100) substrate at various oxygen pressures and at various substrate temperatures by using a laser molecular beam epitaxy system. Their structure was investigated by the Raman spectroscopy and X-ray diffraction. Raman spectra showed that only E2(low) and E2 (high) modes were present in all ZnO films. The E2 (low) mode peak changed from disperse to sharp at first and then became more dispersed as either the oxygen pressure or the substrate temperature increased. Its intensity reached a maximum either under the oxygen pressure of 1 Pa or at 773 K. The analyses showed that the sharper and stronger the E2 (low) mode peak, the better the crystal quality, which was confirmed by the X-ray diffraction. Moreover, every E2 (high) mode peak shifted to lower Raman frequencies compared with ZnO single crystal, implying that a tensile stress occurred in all films, which was also proved by the X-ray diffraction. All results indicated that Raman scattering is one of the most useful methods to investigate the structure of ZnO films. In addition, the intensity of Si Raman scattering was enhanced in our results, which might be due to surface-enhanced Raman spectroscopy.

12

Charakteryzacja diod p-i-n wytworzonych metodą implantacji warstw epitaksialnych 4H-SiC jonami glinu

Kwietniewski N., Pazio K., Sochacki M., Szmidt J., Droździel A., Kulik M., Prucnal S., Pyszniak K., Rawski M., Turek M., Żuk J.

Elektronika : konstrukcje, technologie, zastosowania

|

2009

|

Vol. 50, nr 6

32-35

PL

W pracy opisano wytwarzanie i charakteryzację diod p-i-n wytwarzanych w strukturach epitaksjalnych 4H-SiC. W celu uzyskania warstw typu p⁺ wykonano 4-krotną implantację jonami Al przy całkowitej dawce 7,1 · 10¹⁴ cm⁻2² dla uzyskania prostokątnego rozkładu głębokościowego. Implantację prowadzono przy temperaturze tarczy 500°C z użyciem implanatora jonów UNIMAS wyposażonego w plazmowe źródło jonów naszej konstrukcji. Zaimplantowany materiał został następnie wygrzany w argonie przez 20 min. w t = 1600°C. Przeprowadzono badania rozkładów głębokościowych SIMS oraz rozpraszania mikro-ramanowskiego. Z pomiarów metodą c-TLM wyznaczono wartości rezystancji charakterystycznej kontaktów. Pomiary Halla wykazały, że koncentracja nośników w warstwie implantowanej p⁺ o grubości 350 nm zawiera się w przedziale 3...4 · 10¹⁸ cm⁻³ Gęstość prądu wytworzonych diod osiąga maksymalną wartość 220 A/cm² przy polaryzacji w kierunku przewodzenia 10 V, natomiast napięcie przebicia zawiera się w granicach 550...600 V.

EN

We report on fabrication and characterization of 4H-SiC p-i-n diodes. In order to obtain p⁺ -type layer, a four energy Al box-like profile was implanted with atotal fluence of 7,1 • 10 ¹¹ cm ⁻² at 500°C, using the UNIMAS ion implanter equipped with a plasma ion source of our construction. Implanted material was subsequently annealed for 20 min at 1600°C in argon. SIMS depth profiling and micro-Raman scattering investigations we re performed. The values of specific contact resistance were determined by the c-TLM method. The performed Hall measurements have shown that 350 nm thick p⁺ layers are characterized by carrier concentration of 3...4 • 10 ¹⁸ cm ⁻³. The fabricated diodes have probed forward current density up to 220 A/cm² at 10 V forward drop and 550...600 V breakdown voltages.

13

Raman spectroscopy of Zn1-xCoxO bulk mixed crystals

Szuszkiewicz W, Morhange J F, Schumm M, Lentze M, Gołacki Z, Skupiński P, Grasza K, Geurts J

Materials Science Poland

|

2008

|

Vol. 26, No. 4

1045--1052

EN

We report on a study of structural properties of Zn1-xCoxO by micro- and macro-Raman scattering from phonons. Bulk mixed crystals (x ≤ 0,03), grown by chemical vapour transport were investigated between 5 K and 295 K. Beside the common eigenmodes of the ZnO host lattice, we observed disorder-induced lattice vibration modes and a structure, tentatively assigned to a local vibration mode of the Co impurity. Our results are compared with literature data of other ZnO-based diluted magnetic semiconductors such as (Zn,Mn)O.

14

Raman scattering studies of MBE-grown ZnTe nanowires

Szuszkiewicz W., Morhange J. F., Dynowska E., Janik E., Zaleszczyk W., Presz A., Domagała J. Z., Caliebe W., Karczewski G., Wojtowicz T.

Materials Science Poland

|

2008

|

Vol. 26, No. 4

1054--1059

EN

We report on the first studies of the optical properties of MBE-grown ZnTe nanowires (NWs). The growth of ZnTe NWs was based on the Au-catalyzed vapour–liquid–solid mechanism and was performed on (001), (011), or (111)B-oriented GaAs substrates. Investigated NWs have a zinc-blende structure, the average diameter of about 30 nm, and typical length between 1 and 2 μm. Their growth axes are oriented along <111>-type directions of the substrate. The structural characterization of the NWs was performed by means of X-ray diffraction, using the synchrotron radiation corresponding to the wavelength of CuKα1 radiation W1 beamline at Hasylab DESY). The macro-Raman spectra of either as-grown NWs on GaAs substrate or of NWs removed from substrate and deposited onto Si were collected at temperatures from 15 K to 295 K using Ar+ and Kr+ laser lines. Strong enhancement of ZnTe-related LO-phonon structure was found for an excitation close to the exciton energy. Our studies revealed also the presence of small trigonal Te precipitates, typical of tellurium compounds.

15

Szkło nieliniowe dla fotoniki. Cz. 2, Nieliniowość mechaniczna i termiczna szkła

Romaniuk R.

Elektronika : konstrukcje, technologie, zastosowania

|

2008

|

Vol. 49, nr 3

100-105

PL

W artykule, który jest drugą częścią cyklu prac o szkłach nieliniowych, dokonano przeglądu nieliniowych właściwości mechanicznych i termicznych szkieł nieliniowych przeznaczonych dla fotoniki. Określono obszary mechanicznej i termicznej nieliniowości statycznej i dynamicznej szkieł, bazując na wzajemnym oddziaływaniu ośrodka, fali optycznej i pól termomechanicznych. Zebrano te nieliniowe cechy mechaniczne i termiczne szkieł, które decydują o ich nieliniowych właściwościach optycznych.

EN

The paper, which is the second part of a cycle on nonlinear glasses, digests the nonlinear mechanical and thermal properties of glasses for photonics. The areas of mechanical and thermal, dynamic and static nonlinearities of glasses were determined basing on mutual interaction of medium, optical wave and interacting external thermomechanical fields. There were gathered these nonlinear mechanical and thermal properties of glasses which decide of their nonlinear optical properties.

16

Badania właściwości fizycznych warstwy SiO2 pod bramką aluminiową

Borowicz L., Rzodkiewicz W., Kulik M., Borowicz P.

Elektronika : konstrukcje, technologie, zastosowania

|

2008

|

Vol. 49, nr 11

29-32

PL

W pracy omówiono fizyczne właściwości warstwy dwutlenku krzemu położonego pod bramką aluminiową, ze szczególnym uwzględnieniem zachodzącego w tejże warstwie ciśnienia i występujących tam struktur. W badaniach wykorzystane zostały następujące narzędzia pomiarowe: spektrometr ramanowski, interferometr Fizeau i mikrointerferometr MII4.

EN

In this paper physical properties of silicon dioxide under the aluminium gate were described. Particularly, in our studies a pressure and two kinds of structures occuring in the layer were taken into account. In our investigations, the following measurements tools such as raman spectrometer, Fizeu interferometer and MII4 microinterferometerwere applied.

17

Experimental challenges for approaching local strain determination in silicon by nano-Raman spectroscopy

Zhu L., Atesang J., Dudek P., Hecker M., Rinderknecht J., Ritz Y., Geisler H., Herr U., Geer R., Zschech E.

Materials Science Poland

|

2007

|

Vol. 25, No. 1

19--31

EN

Raman intensity enhancement induced by nanoprobes (metal particles and metallised tips) approached to a strained silicon sample surface is reported. With silver nanoparticles deposited onto a silicon surface, high enhancements in the vicinity of particles were observed. Furthermore, metallised tips were scanned inside the spot of the laser used for Raman measurements. Both silver-coated and pure silver tips, mounted onto a tuning fork, indicated high Raman signal enhancement for optimised tip position within the laser spot. Atomic force microscopy was performed on a structured sample to investigate the stability of these tips. Focused ion beam was utilized to refine and to re-sharpen pure silver tips after the measurements. Complementary measurements were performed using pure tungsten tips. Due to the high hardness of W wires, a special pre-etching technique was applied in this case.

18

Badanie mieszanych kryształów metodą ramanowskiego rozpraszania światła

Ochmański K., Hulewicz A.

Elektronika : konstrukcje, technologie, zastosowania

|

2004

|

Vol. 45, nr 3

26-28

PL

W pracy przedstawiono badania półprzewodników kryształów mieszanych Zn1-xBexSe metodą ramanowskiego rozpraszania światła w zakresie temperatur 292; 225; 150; i 77 K dla stężenia Be z przedziału 0 < x < 0,25. Dla spolaryzowanych widm ramanowskich podłużne LO i poprzeczne TO mody optyczne odpowiadające pojedyńczym modom ZnSe-, BeSe- podobnym dla czystych kryształów są wyraźne. Teoretyczne obliczenia częstotliwości modów ZnSe-, BeSe- podobnych mieszanych kryształów Zn1-xBexSe zostały przeprowadzone przez zastosowanie teoretycznego modelu MREI [1, 2]. Dokonano również porównania modów optycznych Zn1-xBexSe dla różnych stężeń Be.

EN

In the paper, results of observations concerned Raman scattering in Zn1-xBexSe semiconductor mixed crystals are presented. Measurements of Zn1-xBexSe mixed crystals were made for temperatures 292; 225; 150 and 77 K with. Be content included in the range 0 < x < 0,25. From the polarized Raman spectra, the longitudinal optical (LO) and transverse optical (TO) modes that correspond to ZnSe-, BeSe- like single crystals, are distinguished. Theoretical calculations of the frequencies of the ZnSe-, BeSe- like modes of Zn1-xBexSe semiconductor mixed crystals were performed using MREI model. Furthermore, the optical modes of Zn1-xBexSe were compared for different concentrations of Be.