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Wyszukujesz frazę "Witkowski, B. S." wg kryterium: Autor


Tytuł:
ZnO Nanopowders by a Microwave Hydrothermal Method - Influence of the Precursor Type on Grain Sizes
Autorzy:
Wolska, E.
Witkowski, B. S.
Godlewski, M.
Powiązania:
https://bibliotekanauki.pl/articles/2048108.pdf
Data publikacji:
2011-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.67.-n
61.43.Gt
81.07.Wx
78.55.Et
Opis:
Two series of ZnO nanopowders obtained by a microwave hydrothermal method are examined. We used two different zinc precursors (zinc chloride (ZnCl$\text{}_{2}$) and zinc nitrate hexahydrate (N$\text{}_{2}$O$\text{}_{6}$Zn·6H$\text{}_{2}$O)). Both types of nanopowders show a bright emission in a visible light, including the band edge emission, which indicates their good crystallographic quality. Results of scanning electron microscopy, photo- and cathodoluminescence investigations are presented.
Źródło:
Acta Physica Polonica A; 2011, 119, 5; 683-685
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Properties of thin films of high-k oxides grown by atomic layer deposition at low temperature for electronic applications
Autorzy:
Gieraltowska, S
Wachnicki, Ł
Witkowski, B S
Godlewski, M
Guziewicz, E
Powiązania:
https://bibliotekanauki.pl/articles/173591.pdf
Data publikacji:
2013
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
high-k oxides
composite layers
atomic layer deposition
transparent electronics
zinc oxide
Opis:
Thin films of high-k oxides are presently used in semiconductor industry as gate dielectrics. In this work, we present the comparison of structural, morphological and electrical properties of binary and composite layers of high-k oxides that include hafnium dioxide (HfO2), aluminum oxide (Al2O3) and zirconium dioxide (ZrO2). We deposit thin films of high-k oxides using atomic layer deposition (ALD) and low growth temperature (60–240 °C). Optimal technological growth parameters were selected for the maximum smoothness, amorphous microstructure, low leakage current, high dielectric strength of dielectric thin films, required for gate applications. High quality of the layers is confirmed by their introduction to test electronic structures, such as thin film capacitors, transparent thin film capacitors and transparent thin film transistors. In the latter structure we use semiconductor layers of zinc oxide (ZnO) and insulating layers of high-k oxide grown by the ALD technique at low temperature (no more than 100 °C).
Źródło:
Optica Applicata; 2013, 43, 1; 17-25
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Temperature-dependence of cathodoluminescence of zinc oxide monolayers obtained by atomic layer deposition
Autorzy:
Witkowski, B S
Wachnicki, L
Nowakowski, P
Suchocki, A
Godlewski, M
Powiązania:
https://bibliotekanauki.pl/articles/173941.pdf
Data publikacji:
2013
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
zinc oxide
cathodoluminescence
profiling
temperature-dependence
localization
Opis:
We performed cathodoluminescence (CL) investigations of zinc oxide monolayers obtained by atomic layer deposition. Layers of different thickness were deposited on commercial GaN/sapphire templates. Scanning electron microscopy (SEM) system equipped with CL allows direct comparison of SEM images and CL maps, taken from exactly the same areas of samples. In addition to SEM and CL images, CL profiling was performed by collecting the CL spectra at different accelerating voltages. The CL profiling allows to distinguish the emissions from a surface and volume of samples. An inter-link between samples microstructure and emission properties is investigated. Shifts of emission bands, associated by us with the localization effects, are observed. CL investigations are supported by photoluminescence (PL) measurements, which are characterized by a higher spectral resolution. PL investigations allow determination of the origin of emission bands.
Źródło:
Optica Applicata; 2013, 43, 1; 187-194
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Struktury fotowoltaiczne oparte o heterozłącze ZnO/Si
Photovoltaic Structures Based on Heterojunction Zno/Si
Autorzy:
Pietruszka, R.
Łuka, G.
Witkowski, B. S.
Kopalko, K.
Zielony, E.
Biegański, P.
Płaczek-Popko, E.
Godlewski, M.
Powiązania:
https://bibliotekanauki.pl/articles/952439.pdf
Data publikacji:
2014
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Elektrotechniki
Tematy:
fotowoltaika
tlenek cynku
metoda osadzania warstw atomowych
photovoltaic
zinc oxide
Opis:
Warstwy tlenku cynku otrzymane metodą osadzania warstw atomowych ALD zostały użyte jako n-typu partner dla p-typu krzemu. Jako przezroczystą górną elektrodę wybrano warstwę tlenku cyku domieszkowaną glinem (tak zwana warstwa TCO – Transparent Conductive Oxide). Użyto tanich podłóż krzemowych o niezoptymalizowanej dla zastosowań fotowoltaicznych grubości. W niniejszej pracy badano proste struktury fotowoltaiczne ZnO/Si w celu redukcji kosztów produkcji energii elektrycznej pozyskiwanej za pomocą ogniw fotowoltaicznych. Zmierzona sprawność zoptymalizowanych częściowo (warstwy ZnO) ogniw fotowoltaicznych wyniosła 6%.
We report on the properties of photovoltaic (PV) structures based on thin films of n-type zinc oxide grown by atomic layer deposition method on a cheap silicon substrate. Thin films of ZnO are used as n-type partner to p-type Si (110) and, when doped with Al, as a transparent electrode. PV structures with different electrical parameters and thicknesses of ZnO layers were deposited to determine the optimal performance of PV structures. The best response we obtained for the structure with ZnO layer thickness of 800 nm. The soobtained PV structures show 6% efficiency.
Źródło:
Prace Instytutu Elektrotechniki; 2014, 264; 113-123
0032-6216
Pojawia się w:
Prace Instytutu Elektrotechniki
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Cathodoluminescence Profiling for Checking Uniformity of ZnO and ZnCoO Thin Films
Autorzy:
Witkowski, B. S.
Łukasiewicz, M. I.
Wolska, E. A.
Kopalko, K.
Kowalski, B. J.
Guziewicz, E.
Godlewski, M.
Powiązania:
https://bibliotekanauki.pl/articles/2048105.pdf
Data publikacji:
2011-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.15.Gh
78.30.Fs
78.60.Hk
Opis:
We employ scanning electron microscopy and cathodoluminescence for evaluation of uniformity of ZnCoO films obtained by the atomic layer deposition. Cathodoluminescence quenching by Co ions allows us to detect (regions of weaker light emission) Co accumulations, with the resolution limited by diffusion length of secondary carriers.
Źródło:
Acta Physica Polonica A; 2011, 119, 5; 675-677
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Properties and Characterization of ALD Grown Dielectric Oxides for MIS Structures
Autorzy:
Gierałtowska, S.
Sztenkiel, D.
Guziewicz, E.
Godlewski, M.
Łuka, G.
Witkowski, B. S.
Wachnicki, Ł.
Łusakowska, E.
Dietl, T.
Sawicki, M.
Powiązania:
https://bibliotekanauki.pl/articles/2048118.pdf
Data publikacji:
2011-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.15.Gh
77.55.-g
77.84.Bw
81.05.Ea
Opis:
We report on an extensive structural and electrical characterization of undergate dielectric oxide insulators Al$\text{}_{2}$O$\text{}_{3}$ and HfO$\text{}_{2}$ grown by atomic layer deposition. We elaborate the atomic layer deposition growth window for these oxides, finding that the 40-100 nm thick layers of both oxides exhibit fine surface flatness and required amorphous structure. These layers constitute a base for further metallic gate evaporation to complete the metal-insulator-semiconductor structure. Our best devices survive energizing up to ≈ 3 MV/cm at 77 K with the leakage current staying below the state-of-the-art level of 1 nA. At these conditions the displaced charge corresponds to a change of the sheet carrier density of 3 × 10$\text{}^{13}$ cm$\text{}^{-2}$, which promises an effective modulation of the micromagnetic properties in diluted ferromagnetic semiconductors.
Źródło:
Acta Physica Polonica A; 2011, 119, 5; 692-695
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Si/ZnO nanorods with Ag nanoparticles/AZO heterostructures in PV applications
Autorzy:
Gwóźdź, K.
Płaczek-Popko, E.
Gumienny, Z.
Zielony, E.
Pietruszka, R.
Witkowski, B. S.
Wachnicki, Ł.
Gierałtowska, S.
Godlewski, M.
Chang, L. B.
Powiązania:
https://bibliotekanauki.pl/articles/201432.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
solar cells
ZnO
Si
heterojunction
nanorods
nanoparticles
ogniwa słoneczne
nanopręty
nanocząstki
Opis:
Our studies focus on test structures for photovoltaic applications based on zinc oxide nanorods grown using a low-temperature hydrothermal method on a p-type silicon substrate. The nanorods were covered with silver nanoparticles of two diameters – 20–30 nm and 50–60 nm – using a sputtering method. Scanning electron microscopy (SEM) micrographs showed that the deposited nanoparticles had the same diameters. The densities of the nanorods were obtained by means of atomic force microscope (AFM) images. SEM images and Raman spectroscopy confirmed the hexagonal wurtzite structure of the nanorods. Photoluminescence measurements proved the good quality of the samples. Afterwards an atomic layer deposition (ALD) method was used to grow ZnO:Al (AZO) layer on top of the nanorods as a transparent electrode and ohmic Au contacts were deposited onto the silicon substrate. For the solar cells prepared in that manner the current-voltage (I-V) characteristics before and after the illumination were measured and their basic performance parameters were determined. It was found that the spectral characteristics of a quantum efficiency exhibit an increase for short wavelengths and this behavior has been linked with the plasmonic effect.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2016, 64, 3; 529-533
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optical Characterization of ZnO Nanorods Grown by the Ultra-Fast and Low Temperature Hydrothermal Process
Autorzy:
Witkowski, B.
Ivanov, V.
Wachnicki, Ł.
Gierałtowska, S.
Godlewski, M.
Powiązania:
https://bibliotekanauki.pl/articles/1185890.pdf
Data publikacji:
2016-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.67.-n
61.46.+w
81.10.Dn
77.84.Bw
Opis:
The results of photoluminescence investigations of zinc oxide nanorods are reported. These nanorods grown on undoped silicon substrates were obtained by low temperature and ultra-fast version of a microwave-assisted hydrothermal method. The photoluminescence investigations show very high quality of the obtained material. From photoluminescence studies we conclude the lack of carrier localization effects. The photoluminescence is dominated by band gap edge emission of bound excitonic (donor bound excitons) origin. Thus, the photoluminescence quenching observed at increased temperatures is associated with thermal ionization of shallow donors. From photoluminescence analysis (changes of photoluminescence line width) a strength of exciton-acoustic phonon coupling is evaluated.
Źródło:
Acta Physica Polonica A; 2016, 130, 5; 1199-1201
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Surface roughness of the Ti-6Al-4V ELI titanium alloy after the turning process
Autorzy:
Rosik, R.
Kępczak, N.
Sikora, M.
Witkowski, B.
Wójcik, R.
Midera, S.
Powiązania:
https://bibliotekanauki.pl/articles/379242.pdf
Data publikacji:
2019
Wydawca:
Stowarzyszenie Komputerowej Nauki o Materiałach i Inżynierii Powierzchni w Gliwicach
Tematy:
statistic methods
titanium alloy
surface roughness
turning
metody statystyczne
stop tytanu
chropowatość powierzchni
toczenie
Opis:
Purpose: The purpose of this article is discussing the methods of determining the surface roughness of the Ti-6Al-4V ELI titanium alloy obtained after longitudinal turning. The method of determining the mathematical model used for determining the Rz roughness parameter and then the results obtained were compared with values measured and calculated on the basis of equations available in the literature. Design/methodology/approach: The mathematical model in the form of multiple regression function of exponential polynomial was determined using the algorithm of the acceptance and rejection method. The data for calculations was obtained by measuring the surface roughness after turning with different machining parameter values. Findings: A mathematical model was elaborated in the form of a multiple regression function, enabling calculation of the Rz parameter describing the Ti-6Al-4V ELI titanium alloy surface roughness after longitudinal turning. The verification of the dependence obtained confirmed its accuracy. Research limitations/implications: Further research should encompass other values of machining plate geometry, as well as other types of cooling and lubricating fluids and method of applying them. Practical implications: The mathematical model can be helpful when choosing the conditions in which the turning process will be carried out. It also constitutes a basis for further optimisation of that process. Originality/value: The results of this research are a novelty on a worldwide scale. No research of this type has been conducted with regard to analyses and optimisation of longitudinal turning of the Ti-6Al-4V ELI titanium alloy.
Źródło:
Archives of Materials Science and Engineering; 2019, 98, 2; 74-80
1897-2764
Pojawia się w:
Archives of Materials Science and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Characterization of n-ZnO/p-GaN Heterojunction for Optoelectronic Applications
Autorzy:
Wachnicki, L.
Gieraltowska, S.
Witkowski, B.
Figge, S.
Hommel, D.
Guziewicz, E.
Godlewski, M.
Powiązania:
https://bibliotekanauki.pl/articles/1399138.pdf
Data publikacji:
2013-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
85.30.Kk
61.05.cp
81.05.Dz
Opis:
An important feature of zinc oxide and gallium nitride materials are their similar physical properties. This allows to use them as a p-n junction materials for applications in optoelectronics. In earlier work we presented use of ZnO as a transparent contact to GaN, which may improve external efficiency of LED devices. In this work we discuss properties of a n-ZnO/p-GaN heterostructure and discuss its optimization. The heterostructure is investigated by us for possible applications, e.g. in a new generation of UV LEDs or UV light detectors.
Źródło:
Acta Physica Polonica A; 2013, 124, 5; 869-872
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optical and Structural Characterization of Zinc Oxide Nanostructures Obtained by Atomic Layer Deposition Method
Autorzy:
Wachnicki, Ł.
Witkowski, B.
Gierałtowska, S.
Kopalko, K.
Godlewski, M.
Guziewicz, E.
Powiązania:
https://bibliotekanauki.pl/articles/1492916.pdf
Data publikacji:
2011-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.07.Bc
82.47.Rs
68.55.-a
81.15.Aa
Opis:
Zinc oxide is a II-VI semiconductor material which is gaining increasing interest in various fields such as biology, medicine or electronics. This semiconductor reveals very special physical and chemical properties, which imply many applications including a transparent electrode in solar cells or LED diodes. Among many applications, ZnO is also a prospective material for sensor technology, where developed surface morphology is very advantageous. In this work we present ZnO nanowires growth using atomic layer deposition method. ZnO nanowires were obtained using controlled physical properties. As a substrate we used gallium arsenide with gold-gallium eutectic droplets prepared on the surface at high temperature. To obtain the eutectic solution there was put a gold thin film on GaAs through the sputtering and then we annealed the sample in a nitrogen gas flow. The so-prepared substrate was applied for growth of ZnO nanowires. We used deionized water and zinc chloride as oxygen and zinc precursors, respectively. The eutectic mixture serves as a catalyst for the ZnO nanowires growth. Au-Ga droplets flow on the front of ZnO nanowires. Scanning electron microscopy images show ZnO nanorods in a form of crystallites of up to 1 μm length and a 100 nm diameter. It is the first demonstration of the ZnO nanowires growth by atomic layer deposition using the vapour-liquid-solid approach.
Źródło:
Acta Physica Polonica A; 2011, 120, 5; 905-907
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Photoluminescence and Chromaticity Properties of ZnO Nanopowders Made by a Microwave Hydrothermal Method
Autorzy:
Wolska, E.
Sibera, D.
Witkowski, B.
Yatsunenko, S.
Pełech, I.
Narkiewicz, U.
Godlewski, M.
Powiązania:
https://bibliotekanauki.pl/articles/1492917.pdf
Data publikacji:
2011-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.67.-n
61.43.Gt
81.07.Wx
78.55.Et
Opis:
Four series of ZnO nanopowders obtained by a microwave hydrothermal method are examined. Two different solvents (ethanol and distilled water) and different values of pressure during heating in the reactor were used. The obtained nanopowders show a bright emission covering visible light spectral region, including the band edge emission. Results of scanning electron microscopy, X-ray diffraction, photo- and cathodoluminescence investigations and also CIE1961 chromaticity diagram are presented.
Źródło:
Acta Physica Polonica A; 2011, 120, 5; 908-910
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
(Zn,Cu)O Films by Atomic Layer Deposition - Structural, Optical and Electric Properties
Autorzy:
Łukasiewicz, M.
Witkowski, B.
Wachnicki, Ł.
Kopalko, K.
Gierałtowska, S.
Wittlin, A.
Jaworski, M.
Guziewicz, E.
Godlewski, M.
Powiązania:
https://bibliotekanauki.pl/articles/1492571.pdf
Data publikacji:
2011-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
68.55.Ln
68.55.Nq
78.66.Hf
81.15.Kk
Opis:
ZnCuO thin films have been deposited on silicon, glass and quartz substrates by atomic layer deposition method, using reactive organic precursors of zinc and copper. As zinc and copper precursors we applied diethylzinc and copper(II) acetyloacetonate. Structural, electrical and optical properties of the obtained ZnCuO layers are discussed based on the results of scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, atomic force microscopy, the Hall effect and photoluminescence investigations.
Źródło:
Acta Physica Polonica A; 2011, 120, 6A; A-034-A-036
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
RBS/Channeling Analysis of Zinc Oxide Films Grown at Low Temperature by Atomic Layer Deposition
Autorzy:
Ratajczak, R.
Stonert, A.
Guziewicz, E.
Gierałtowska, S.
Krajewski, T.
Luka, G.
Wachnicki, L.
Witkowski, B.
Godlewski, M.
Powiązania:
https://bibliotekanauki.pl/articles/1400467.pdf
Data publikacji:
2013-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
77.55.hf
81.05.Dz
81.15.Hi
68.55.ag
82.80.Yc
61.85.+p
Opis:
The results of the Rutherford backscattering/channeling study of ZnO layers are presented. ZnO layers were deposited on the silicon single crystals and GaN epitaxial layers at low temperature by atomic layer deposition. Deposition temperature varied between 100 and 300°C. A random spectra analysis was performed to determine layer thickness and composition. In turn, analysis of the aligned spectra allows us to study evolution of ingrown defects. The Rutherford backscattering study supports the results of X-ray photoelectron spectroscopy measurements, performed separately, that the ZnO-ALD layers deposited at low temperature contain a higher oxygen content. Composition measurements, performed as a function of growth temperature, show that oxygen content decreases with the increasing temperature of the atomic layer deposition growth process.
Źródło:
Acta Physica Polonica A; 2013, 123, 5; 899-903
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sprawozdania z piśmiennictwa polskiego w dziedzinie nauk matematyczno-fizycznych za rok 1891
Revue de travaux scientifiques polonais publiés en 1891 sur les sciences mathématiques et physiques
Autorzy:
Biernacki, Wiktor
Birkenmajer, L.
Ciemniewski, M.
Czajewicz, A.
Dickstein, S.
Dziwiński, B.
Gosiewski, Wł.
Natanson, E.
Natanson, Wł.
Witkowski, A.
Powiązania:
https://bibliotekanauki.pl/articles/1975599.pdf
Data publikacji:
1893
Wydawca:
Towarzystwo Naukowe Warszawskie
Źródło:
Prace Matematyczno-Fizyczne; 1893, 4, 1; 185-230
0867-5570
Pojawia się w:
Prace Matematyczno-Fizyczne
Dostawca treści:
Biblioteka Nauki
Artykuł

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