Wyniki wyszukiwania - Biblioteka Nauki

1

Stability of Finite-size Argon Thin Film Coating Single Wall Carbon Nanotube

100%

Kośmider M. , Dendzik Z. , Żurek S. , Górny K.

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2009

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tom Vol. 13, No 3

187-197

EN

The structure and the dynamics of the argon thin film coating (15,4) and (12,12) carbon nanotubes have been studied in a series of molecular dynamic simulations. In the studied temperature regime, the argon atoms in the thin film were well localized. Structural changes and diffusion process inside the argon layers were not been observed. The influence of the chirality and the radius of the nanotube to the cluster properties is also reported.

2

Investigations of electrical properties of Eu- and Pd-doped titanium dioxide thin films on silicon

100%

Domaradzki J. , Borkowska A. , Kaczmarek D. , Prociow E. L.

|

2007

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tom Vol. 37, nr 1-2

133-137

EN

In this work, investigations of electrical properties of Eu- and Pd-doped TiO2 thin films have been outlined. Thin films were deposited by low pressure hot target reactive magnetron sputtering from metallic Ti-Eu-Pd mosaic target on conventional silicon wafers. For electrical characterization of prepared thin films both temperature dependent resistivity and current to voltage (I-V) characteristics have been examined. It has been shown that incorporation of Pd and Eu dopants into TiO2 matrix modified its properties to obtain n-type oxide-semiconductor which is electrically and optically active at room temperature. Additionally from I-V measurements the formation of heterojunction at the interface of thin film-silicon was confirmed.

3

Study of the surface relaxation and single vacancy formation in very thin Cu (001) film by using MAEAM

100%

Wen Y.-N.

Open Physics

|

2014

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tom 12

|

nr 8

559-564

EN

The surface relaxation and the formation of a single vacancy in very thin Cu (001) film formed by 2 ∼ 14 atomic layers have been studied by using MAEAM and MD simulation. For the surface relaxtion, the highest surface energy is in the l = 2 atomic layers. The multilayer relaxation mainly occurs between the first two atomic layers, and the maximum contractive displacement is obtained in the very thin Cu (001) film formed by l = 3 atomic layers. For the vacancy formed in l′ = 1 of the very thin Cu (001) film formed by l = 2 ∼ 14 layers, the most difficult site in the film formed by l = 3 atomic layers.

4

Liquid and liquid-gas cooling of machine elements

100%

Mikielewicz J.

|

2002

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tom nr 110

21-45

EN

In the work presented are thermal and hydraulic problems concerned with the liquid films formed by impinging jets. Formulated has been a simple two-dimensional model of the flow and heat transfer in the film. The model is based on simplified equations of mass, momentum and energy balance. Solution of such set of equations enables determination of velocity profile in the film as well as local heat transfer coefficients.

5

Effect of Complexing Agent on the Structural, Optical and Electrical Properties of Polycrystalline Indium Sulfide Thin Films Deposited by Chemical Bath Deposition

100%

Göde F. , Kariper İ. , Güneri E. , Ünlü S.

Acta Physica Polonica A

|

2017

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tom 132

|

nr 3

527-530

EN

Indium sulfide (β-In₂S₃) thin films are synthesized by chemical bath deposition method using three different complexing agent volumes, triethanolamine (TEA) (0.30, 0.45, and 0.60 ml). The effect of complexing agent on the structural, morphological, optical and electrical properties of chemically deposited indium sulfide (β-In₂S₃) thin films have been investigated in this work. The characterization of the present films is carried out using X-ray diffraction, scanning electron microscopy, UV-vis spectroscopy and electrical measurements. The structure of the films is polycrystalline with a cubic phase of β-In₂S₃. Firstly, the band gap of the film decreases from 3.74 eV to 3.15 eV by adding 0.30 ml TEA. Then, it increases to 3.79 eV with increasing TEA. Nevertheless, previously, the refractive index of the films increases from 2.13 to 2.67 for the 0.30 mL TEA and then it decreases to the value of 2.11 with increasing TEA. Extinction coefficient, real and dielectric constant of the films are calculated using the absorption and transmittance spectra. Firstly, the electrical resistivity of the films decreases from 3.46×10⁸ Ω cm to 1.33×10⁷ Ω cm by adding 0.30 ml TEA. Then, it increases to the value of 2.16×10⁹ Ω cm with increasing TEA. Eventually, the more conductive film with worm-like morphology detected from the scanning electron microscopy is synthesized using 0.30 ml TEA. These results show that complexing agent has an important effect on the structural, morphological, optical and electrical properties of the deposited films.

6

Influence of pH on the Structural and Optical Properties of Polycrystalline MnTe₂ Thin Films Produced by Chemical Bath Deposition Method

100%

Kariper İ. , Göde F.

Acta Physica Polonica A

|

2017

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tom 132

|

nr 3

531-534

EN

Polycrystalline manganese ditelluride (MnTe₂) thin films are synthesized on commercial glass substrates by chemical bath deposition technique at different pH values (pH = 9, 10, 11 and 12). The effect of pH on the structural and optical properties of chemically deposited MnTe₂ thin films have been investigated in this study. The structure and optical properties of the films are characterized by X-ray diffraction and optical absorption spectroscopy. The X-ray diffraction results suggest that the films are polycrystalline with a mixture of dominant cubic MnTe₂ phase and few traces of orthorhombic MnTeO₃ and MnTe₂O₅ phases. The optical band gap of the films increases approximately from 1.66 eV to 2.62 eV with increasing pH. Moreover, optical parameters of the films such as refractive index, extinction coefficient, real and imaginary dielectric constants are investigated using absorption and transmittance spectra taken from the UV-vis spectrophotometer. At 600 nm wavelength, refractive index and extinction coefficient values vary in the range of 1.39-1.55 and 0.17-0.23, respectively. An increase in optical band gap could be attributed to the quantum confinement effect.

7

ZnO thin film as methane sensor

100%

Mitra P. , Mukhopadhyay A. K.

|

2007

|

tom Vol. 55, nr 3

281-285

EN

Methane (CH4) sensitivity of zinc oxide (ZnO) thin film has been studied in the present work. The sensor element comprises of a chemically fabricated ZnO semiconducting layer and a layer of palladium (Pd) as catalyst. The catalyst layer was formed on the surface of semiconducting ZnO following a wet chemical process from palladium chloride (PdCl2) solution. Fundamental features of a sensor element e.g. sensitivity, response time and recovery process has been studied. The effect of operating temperature on performance of the sensor material has been investigated and a choice of optimum temperature was made at around 200°C. The sensor element exhibited reasonable sensitivity of about 86% at this temperature in presence of 1 vol% methane (CH4) in air.

8

Wide bandpass optical filters with TiO2 and Ta2O5

100%

Asghar M. , Shoaib M. , Placido F. , Naseem S.

Open Physics

|

2008

|

tom 6

|

nr 4

853-863

EN

Complex multilayer thin film filters for optical applications have been designed, prepared and characterized in this work. E-beam reactive evaporation technique has been used as a deposition process. In the first stage, optimized individual film layers of TiO2, Ta2O5, and SiO2 are deposited and characterized optically and structurally before the deposition of multilayered structures. The filter designs are based upon 33 layered SiO2/TiO2 and SiO2/Ta2O5 configurations on glass substrate. These designs are optimized to achieve wideband transmission in the visible spectrum. After deposition, the two filter configurations are characterized optically and structurally using spectrophotometery, atomic force microscopy (AFM), X-ray diffraction (XRD) and scanning electron microscopy (SEM). SiO2/Ta2O5/glass filter has been found sensitive to deposition conditions since high absorption is observed in multilayered configuration for the as-deposited samples. Post-deposition annealing of the filter in the temperature range 150 to 250°C was also performed in order to study the effect of temperature on absorption and spectral characteristics of the filter. Comparison of the two filter configurations was also performed to analyze their suitability for optical applications. Adhesion of the two filters was found to be very good by means of tape-peel test.

9

Optical characterization of the CdZn(S1-x Sex )2 thin films deposited by spray pyrolysis method

100%

Ilican S. , Zor M. , Caglar Y. , Caglar M.

|

2006

|

tom Vol. 36, nr 1

29-37

EN

CdZn(S1-xSex )2 thin films have been deposited onto glass substrates by the spray pyrolysis method at a 275°C substrate temperature. The average optical transmittance of all the films was over 65% in the wavelength range 450-800 nm. The optical absorption studies reveal that the transition is direct with band gap energy values between 2.47-3.04 eV. The optical constants such as refractive index, extinction coefficient and dielectric constants have been calculated for these films. The dispersion parameters such as Eo (single-oscillator energy) and Ed (dispersive energy) have been discussed in terms of the Wemple-DiDomenico single-oscillator model. The values obtained by this method are suitable for many scientific studies and technological applications, such as gas sensors, heat mirrors, transparent electrodes, solar cells and piezoelectric devices.

10

RELEASE AND PERMEATION OF INDOMETHACIN FROM PHOSPHOLIPID COMPLEX FILM GENERATED FROM SPRAY FORMULATIONS

88%

Buatong W. , Nakpheng T. , Dechraksa J. , Saisamuth S.-a. , Kongkhao W. , Srichana T.

Acta Poloniae Pharmaceutica - Drug Research

|

2019

|

tom 76

|

nr 2

329-339

EN

An indomethacin topical spray was prepared using lecithin and a cholesterol derivative as a phospholipid complex in a film. Polyvinylpyrrolidone (PVP) was used as a film-forming agent. Drug penetration through keratinocytes was evaluated as well as cytotoxicity to the keratinocytes and fibroblast cells. The results reveal that the PVP concentration provided fine droplets under a microscope with a low contact angle (12.07°-22.53°). Incorporating PVP in the formulation reduced the hydrodynamic radius or size by 20 times. The SEM and TEM results showed smoother surfaces of the thin film for larger quantities of the PVP film-forming agent in the formulations. It also gave the highest drug penetration when the PVP was 0.5%. However, the film-forming agent can also act as a control release barrier. The percent viabilities of the human keratinocytes and fibroblasts were higher in the indomethacin spray phospholipid complex thin film formulation than the pure drug.

11

Influence of Eu dopant on optical properties of TiO2 thin films fabricated by low pressure hot target reactive sputtering

88%

Borkowska A. , Domaradzki J. , Kaczmarek D.

|

2007

|

tom Vol. 37, nr 1-2

117-122

EN

This work presents the influence of europium dopant on optical properties of TiO2:Eu3+ thin films fabricated by low pressure hot target reactive sputtering. Thin films were deposited from metallic Ti-Eu mosaic target on different substrates (i.e., monocrystalline silicon and SiO2). Selected samples were additionally annealed for 4 hours in an air ambient at 200 °C after deposition. Thin films were examined by means of scanning electron microscopy with energy disperse spectrometer (SEM-EDS), X-ray diffraction (XRD), optical transmission method and photoluminescence (PL). From SEM-EDS measurements total Eu concentration in fabricated thin films was determined. XRD analysis revealed the existence of crystalline TiO2 in the form of anatase and rutile in examined samples with smaller and larger amount of Eu dopant, respectively. Optical transmission method showed that doping with selected amount of Eu results in different shift of the fundamental absorption edge for prepared thin films. PL studies showed a red luminescence of TiO2:Eu3+ thin films. The intensity of luminescence increased with the annealing temperature and decreased with larger amount of europium.

12

Influence of terbium on structure and luminescence of nanocrystalline TiO2 thin films

88%

Wojcieszak D. , Kaczmarek D. , Domaradzki J. , Lukowiak A. , Strek W.

Open Physics

|

2013

|

tom 11

|

nr 2

239-244

EN

In this work analysis of the structural and optical properties of TiO2 thin films doped with terbium has been described. Samples were prepared by a high energy reactive magnetron sputtering process under low pressure of oxygen plasma. X-ray diffraction results have shown that different TiO2 crystal forms have been produced, depending on the amount of Tb dopant. The undoped matrix had rutile structure with crystallites with a size of 8.7 nm, while incorporation of 0.4 at. % of Tb into the film during the sputtering process resulted in anatase structure with bigger crystallites (11.7 nm). Increasing the amount of terbium up to 2 at. % and 2.6 at. % gave rutile structure with crystallites with a size of 6.6 nm for both films. However, Raman spectroscopy has revealed that in the case of TiO2:(2 at. % Tb), except for the rutile form, the presence of fine-crystalline anatase was observed. Moreover, the lack of Raman peaks shift attests to the lack of stress in the titania lattice of all of the TiO2:Tb films. This fact indicates localization of Tb3+ ions on the surface of TiO2 nanocrystals. In the case of optical investigation, results have shown that doping with terbium has a significant influence on the properties of TiO2, but it does not decrease the high transparency of the matrix. The observed changes of the transmission characteristics were produced only due to modification of the TiO2:Tb structure. Photoluminescence measurements have shown that emission of light from TiO2:Tb films occurs when the amount of terbium is 2.6 at. %. Based on the obtained results a scheme of direct energy transfer from titanium dioxide matrix (with rutile structure) to Tb3+ ions has been proposed.

13

Spectral properties and photophysics of arylacetylenes in thin films

88%

Flamini R. , Carlotti B. , Spalletti A. , Marrocchi A.

Organic Photonics and Photovoltaics

|

2014

|

tom 2

|

nr 1

EN

We report the photobehaviour of a series of eight structurally related arylacetylene derivatives, in solution as well as in pristine and PC61BM blended thin-_lms. The formation of both H- and J-aggregates in the solid state have been demonstrated, and, interestingly, an energy transfer from H-aggregates or/and from residual "unstacked" molecules to J-aggregates has been found, the latter being the only emitting species. The fuorescence quenching by PC61BM at di_erent loadings has been studied in blend films, and it has been found particularly effcient in the case of a symmetrical peripheral substitution of the acetylene derivative core. Preliminary time-resolved measurements in emission (ns resolution) and in absorption (fs resolution) con_rmed the H⟶J energy transfer and underlined the presence of delayed fuorescence from Jaggregates, formed by energy transfer from the long-lived first excited singlet state of H-aggregates. In all cases, a homogeneous surface morphology of thin films.

14

Effect of electrostatic field on rupture of thin liquid film on a cylinder

88%

Gorla R. S. R. , Byrd L. W.

|

2001

|

tom Vol. 6, no 1

151-164

EN

The dynamic rupture process of a thin liquid film on a cylinder has been analyzed by investigating the stability under the influence of a non-uniform electrostatic field to finite amplitude disturbances. The dynamics of the liquid film is formulated using the balance equations including a body force term due to van der Waals attractions. The effect of the electric field is included in the analysis only in the boundary condition at the liquid vapor interface. The governing equation for the film thickness was solved by finite difference method as part of an initial value problem for spatial periodic boundary conditions. The electric field stabilizes the film and increases the time to rupture when a long wavelength perturbation is introduced.

15

Hydrogen gas sensors based on nanocrystalline TiO2 thin films

88%

Haidry A. , Schlosser P. , Durina P. , Mikula M. , Tomasek M. , Plecenik T. , Roch T. , Pidik A. , Stefecka M. , Noskovic J. , Zahoran M. , Kus P. , Plecenik A.

Open Physics

|

2011

|

tom 9

|

nr 5

1351-1356

EN

Titanium dioxide thin films are extensively studied for applications in solid state gas sensor devices. Their gas sensing properties are strongly dependent on deposition technique, annealing temperature, film thickness and consequent properties like crystalline structure, grain size or amount of defects and impurities. In this work we report the gas sensing properties of TiO2 thin films prepared by reactive magnetron sputtering technique and subsequently annealed at temperatures 600°C and 900°C. The films were exposed to different concentrations of H2 gas up to 10 000 ppm. Their sensitivity to gas at various operating temperatures, ranging from 250°C to 450°C, was obtained by measuring their resistance.

16

Influence of nanocrystalline structure and composition on hardness of thin films based on TiO2

88%

Kaczmarek D. , Wojcieszak D. , Domaradzki J. , Prociow E. , Placido F. , Lapp S. , Dylewicz R.

Open Physics

|

2011

|

tom 9

|

nr 2

349-353

EN

In this work, the influence of Tb-doping on structure, and especially hardness of nanocrystalline TiO2 thin films, has been described. Thin films were formed by a high-energy reactive magnetron sputtering process in a pure oxygen atmosphere. Undoped TiO2-matrix and TiO2:Tb (2 at. % and 2.6 at. %) thin films, had rutile structure with crystallite sizes below 10 nm. The high-energy process produces nanocrystalline, homogenous films with a dense and close packed structure, that were confirmed by X-ray diffraction patterns and micrographs from a scanning electron microscope. Investigation of thin film hardness was performed with the aid of a nanoindentation technique. Results of measurements have shown that the hardness of all manufactured nanocrystalline films is above 10 GPa. In the case of undoped TiO2 matrix, the highest hardness value was obtained (14.3 GPa), while doping with terbium results in hardness decreasing down to 12.7 GPa and 10.8 GPa for TiO2:(2 at. % Tb) and TiO2:(2.6 at. % Tb) thin films, respectively. Incorporation of terbium into TiO2-matrix also allows modification of the elastic properties of the films.

17

Photocatalytic properties of nanocrystalline TiO2 thin films doped with Tb

88%

Wojcieszak D. , Kaczmarek D. , Domaradzki J. , Prociow E. , Morawski A. , Janus M.

Open Physics

|

2011

|

tom 9

|

nr 2

354-359

EN

In this work photocatalytic properties of TiO2 thin films doped with different amount of Tb have been described. Thin films were prepared by high energy reactive magnetron sputtering process. Comparable photocatalytic activity has been found for all doped TiO2 thin films, while different amounts of Tb dopant (0.4 and 2.6 at. %) results in either an anatase or rutile structure. It was found that the terbium dopant incorporated into TiO2 was also responsible for the amount of hydroxyl groups and water particles adsorbed on the thin film surfaces and thus photocatalytic activity was few times higher in comparison with results collected for undoped TiO2 thin films.

18

Influence of post annealing on optical and structural properties of Eu and Pd-doped TiO2 thin films

75%

Domaradzki J. , Borkowska A. , Kaczmarek D. , Podhorodecki A. , Misiewicz J.

|

2007

|

tom Vol. 37, nr 1-2

51-56

EN

This work presents optical and structural characterization of europium and palladium doped titanium dioxide thin films prepared by modified magnetron sputtering. The metallic Eu and Pd dopants have been co-sputtered from a base Ti target (mosaic target) and deposited on SiO2 substrates. After the deposition samples were additionally annealed in air ambient for 2 hours at the temperatures of 200 °C, 400 °C, 600 °C and 800 °C, respectively. Structural properties of TiO2:(Eu, Pd) thin films were examined using X-ray diffraction (XRD). XRD patterns recorded after thermal treatment showed the dominating TiO2-rutile phase, independently of the temperature of annealing. Optical properties were studied as defined by optical transmission. It has been shown, that doping shifts the fundamental absorption edge of TiO2 toward the longer wavelength range. As the samples were additionally annealed the band gap widening has been observed from 1.7 eV, for as deposited sample up to 2.31 eV for those annealed at 800 °C.

19

Effect of Cu²⁺ Ion Irradiation on Microstructure of Er₂O₃ Coating Layer Formed by MOCVD Method

75%

Tanaka M. , Takezawa M. , Hishinuma Y. , Tanaka T. , Muroga T. , Ikeno S. , Lee S. , Matsuda K.

Acta Physica Polonica A

|

2017

|

tom 131

|

nr 5

1351-1352

EN

Erbium oxide (Er₂O₃) coating is one of the promising methods to restrict tritium permeation and the magneto hydrodynamic pressure drop for advanced breeding blanket systems. Er₂O₃ coating layer on large interior surface area of metal pipe is deposited by using metal organic chemical vapor deposition process. In this work, the influence of Cu²⁺ ion irradiation on microstructure of Er₂O₃ coating layer on stainless steel 316 (SUS 316) substrate by metal organic chemical vapor deposition methods was investigated using scanning electron microscopy, transmission electron microscopy observation and X-ray diffraction analysis. Microstructure observation of Er₂O₃ coating was carried out after 0.00-1.50 dpa Cu²⁺ ion irradiation at 298 K and 773 K. Scanning electron microscopy observation of the surface area on Er₂O₃ thin film revealed the crack generation on surface after Cu²⁺ ion irradiation. X-ray diffraction peaks were identified in Er₂O₃ after Cu²⁺ ion irradiation transmission electron microscopy observations, the formation of interlayer between Er₂O₃ coating and SUS substrate was confirmed. According to transmission electron microscopy-energy dispersive spectroscopy, the interlayer includes Fe and Cr.

20

Influence of iodine on the electrical properties of magnesium phthalocyanines thin film devices

75%

Varghese A. , Menon C.

Open Physics

|

2006

|

tom 4

|

nr 1

20-29

EN

The influence of iodine on the electrical properties of sandwich structures of magnesium phthalocyanine (Mg Pc) thin films with gold and aluminium electrodes has been investigated. The various electrical properties and different electrical parameters of the iodine-doped Mg Pc thin film devices have been estimated and compared with the values of normal Mg Pc devices from the analysis of the current-voltage characteristics. Generally samples showed an asymmetric conductivity both under forward and reverse bias. From our study we found that iodine doped Mg Pc films showed an enhanced electrical conductivity of nearly ten times that of typical Mg Pc. At low voltages the films showed an ohmic conduction with a hole concentration of P0 = 6.34 × 1018 m−3 and hole mobility μ = 9.16 × 10−5 m 2 V−1 s−1, whereas at higher voltage levels the conduction is dominated by space charged limited conduction (SCLC) with a discrete trapping level of 1.33 × 1022 m−3 at 0.63 eV above the valance band edge. The ratio of the free charges to trapped charges (trapping factor) for the doped samples was found to be 1.07 × 10−7. Furthermore the reverse conduction mechanisms have also been investigated. From the current limitations in the reverse condition a strong rectifying behaviour was evident which was attributed to Poole-Frankel emission with a field-lowering coefficient of value 2.24 × 10−5 eV m1/2 V−1/2.