Página 9 dos resultados de 865 itens digitais encontrados em 0.004 segundos

## Ordered arrangements of metal nanoparticles on alpha-cyclodextrin inclusion complexes by magnetron sputtering

Allende, P.; Jara, P.; Orellana, C.; Barrientos, L.
Tipo: Artículo de revista
EN
Relevância na Pesquisa
46.69%
An ordered self-assembly of copper, silver and gold nanoparticles onto crystal faces of a-cyclodextrin/1- octanethiol and 2a-cyclodextrin/1-octylamine inclusion complexes by means of physical vapor deposition (magnetron sputtering) has been achieved. The preferential deposition on the (001) plane of the supramolecular crystal occurs because the –SH and –NH2 groups from the guest molecules found within the a-cyclodextrin protrude into that plane. These functional groups form a two-dimensional hexagonal lattice that interacts with the metal nanoparticles, arranging them in an ordered way.; FONDECYT, Grant Nos. 3100088 and 1080505

## Ordered arrangement of gold nanoparticles on an alpha-cyclodextrin - dodecanethiol inclusion compound produced by magnetron sputtering

Jara, Paul; Gutiérrez, María C.; Yutronic Sáez, Nicolás Ignacio; Monte, Francisco del; Barrientos, Lorena
Tipo: Artículo de revista
EN
Relevância na Pesquisa
46.69%
Publicación ISI; An ordered self-assembly of gold nanoparticles (AuNPs) onto microcrystal faces of a 2 alpha-cyclodextrin-dodecanethiol (2 alpha CD-DDT) inclusion compound (IC) by means of a magnetron sputtering technique was obtained. The preferential deposition on the (001) plane of the alpha CD IC crystal occurs because-SH groups from the guest molecules found within the aCD protrude into that plane. These-SH groups form a two-dimensional hexagonal lattice that interacts with the metal NPs, arranging them in an ordered way.

## Radio Frequency Magnetron Sputtering Deposition of TiO2 Thin Films and Their Perovskite Solar Cell Applications

Chen, Cong; Cheng, Yu; Dai, Qilin; Song, Hongwei
Fonte: Nature Publishing Group Publicador: Nature Publishing Group
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
46.69%
In this work, we report a physical deposition based, compact (cp) layer synthesis for planar heterojunction perovskite solar cells. Typical solution-based synthesis of cp layer for perovskite solar cells involves low-quality of thin films, high-temperature annealing, non-flexible devices, limitation of large-scale production and that the effects of the cp layer on carrier transport have not been fully understood. In this research, using radio frequency magnetron sputtering (RFMS), TiO2 cp layers were fabricated and the thickness could be controlled by deposition time; CH3NH3PbI3 films were prepared by evaporation & immersion (E & I) method, in which PbI2 films made by thermal evaporation technique were immersed in CH3NH3I solution. The devices exhibit power conversion efficiency (PCE) of 12.1% and the photovoltaic performance can maintain 77% of its initial PCE after 1440 h. The method developed in this study has the capability of fabricating large active area devices (40 × 40 mm2) showing a promising PCE of 4.8%. Low temperature and flexible devices were realized and a PCE of 8.9% was obtained on the PET/ITO substrates. These approaches could be used in thin film based solar cells which require high-quality films leading to reduced fabrication cost and improved device performance.

## Bimodal substrate biasing to control \gamma-Al2O3 deposition during reactive magnetron sputtering

Prenzel, Marina; Kortmann, Annika; Stein, Adrian; von Keudell, Achim; Nahif, Farwah; Schneider, Jochen M.
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
46.69%
Al2O3 thin films have been deposited at substrate temperatures between 500{\deg}C to 600{\deg}C by reactive magnetron sputtering using an additional arbitrary substrate bias to tailor the energy distribution of the incident ions. The films were characterized by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The film structure being amorphous, nanocrystalline, or crystalline was correlated with characteristic ion energy distributions. The evolving crystalline structure is connected with different levels of displacements per atom (dpa) in the growing film as being derived from TRIM simulations. The boundary between the formation of crystalline films and amorphous or nanocrystalline films was at 0.9 dpa for a substrate temperature of 500{\deg}C. This threshold shifts to 0.6 dpa for films grown at 550{\deg}C.

## Preparation of electron-doped La(2-x)CexCuO4 thin films with various Ce doping by dc magnetron sputtering

Wu, B. X.; Jin, K.; Yuan, J.; Wang, H. B.; Hatano, T.; Zhao, B. R.; Zhu, B. Y.
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
46.69%
A series of c-axis oriented electron-doped high-Tc superconducting La(2-x)CexCuO4 thin films, from heavily underdoped x=0.06 to heavily overdoped x=0.19, have been synthesized by dc magnetron sputtering technique on (100) SrTiO3 substrates. The influence of various fabrication conditions, such as the deposition temperature and the deposition rate, etc., on the quality of the thin films has been scrutinized. We find that the quality of the films is less sensitive to the deposition temperature in the overdoped region than that in the underdoped region. In the phase diagram of Tc(x), the superconducting dome indicates that the optimally doping level is at the point x=0.105 with the transition temperature Tc0 = 26.5 K. Further more, both the disappearance of the upturn in the $\rho_{xx}$(T) curve at low temperature under H=10 T and the positive differential Hall coefficient, $R_H'=d \rho_{xy}/dH$, are observed around x = 0.15, implying a possible rearrangement of Fermi surface at this doping level.; Comment: 5 pages, 5 figures

## Influence of ionisation zone motion in high power impulse magnetron sputtering on angular ion flux and NbO$_x$ film growth

Franz, Robert; Clavero, César; Kolbeck, Jonathan; Anders, André
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
46.69%
The ion energies and fluxes in the high power impulse magnetron sputtering plasma from a Nb target were analysed angularly resolved along the tangential direction of the racetrack. A reactive oxygen-containing atmosphere was used as such discharge conditions are typically employed for the synthesis of thin films. Asymmetries in the flux distribution of the recorded ions as well as their energies and charge states were noticed when varying the angle between mass-energy analyser and target surface. More positively charged ions with higher count rates in the medium energy range of their distributions were detected in $+\mathbf{E}\times \mathbf{B}$ than in $-\mathbf{E}\times \mathbf{B}$ direction, thus confirming the notion that ionisation zones (also known as spokes or plasma bunches) are associated with moving potential humps. The motion of the recorded negatively charged high-energy oxygen ions was unaffected. NbO$_x$ thin films at different angles and positions were synthesised and analysed as to their structure and properties in order to correlate the observed plasma properties to the film growth conditions. The chemical composition and the film thickness varied with changing deposition angle, where the latter, similar to the ion fluxes...

## Influence of substrate temperature on residual stress and nanomechanical properties of AlN films deposited by magnetron sputtering

Panda, Padmalochan; Ramaseshan, R.; Ravi, N; Mangamma, G.; Jose, Feby; Dash, S.; Suzuki, K.; Suematsu, H.
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
46.69%
We report the crystal structure, surface morphology, residual stress and nanomechanical properties of Wurtzite type AlN thin films on Si (100) substrates using DC reactive magnetron sputtering with a function of substrate temperature (35 to 600 {\deg}C). Evolution of crystallite growth of AlN films was studied by GIXRD and transmission electron microscopy (TEM) and a preferred orientation of a-axis was observed at 400 {\deg}C. The cross-sectional TEM micrograph and selected area diffraction (SAD) pattern of AlN thin films showed that these films exhibited a high degree of orientation as well as the columnar structure. The surface morphology, roughness and grain size of these AlN films were investigated by atomic force microscopy (AFM) as a function of temperature. The residual stress of these films was calculated by sin2 technique and found that they are varying from tensile to compressive with temperature. Nanoindentation hardness (H) of these films ranged between 12.8-19 GPa. We have observed an optimum deposition temperature of 400 {\deg}C for preferentially a-axis oriented AlN film with desired surface roughness and residual stress for surface acoustic wave devices (SAW).

## Time resolved measurement of film growth during reactive high power pulsed magnetron sputtering (HIPIMS) of titanium nitride

Mitschker, Felix; Prenzel, Marina; Benedikt, Jan; Maszl, Christian; von Keudell, Achim
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
46.69%
The growth rate during reactive high power pulsed magnetron sputtering (HIPIMS) of titanium nitride is measured with a temporal resolution of up to 25 us using a rotating shutter concept. According to that concept a 200 um slit is rotated in front of the substrate synchronous with the HIPIMS pulses. Thereby, the growth flux is laterally distributed over the substrate. By measuring the resulting deposition profile with profilometry and with x-ray photoelectron spectroscopy, the temporal variation of the titanium and nitrogen growth flux per pulse is deduced. The analysis reveals that film growth occurs mainly during a HIPIMS pulse, with the growth rate following the HIPIMS phases ignition, current rise, gas rarefaction, plateau and afterglow. The growth fluxes of titanium and nitrogen follow slightly different behaviors with titanium dominating at the beginning of the HIPIMS pulse and nitrogen at the end of the pulse. This is explained by the gas rarefaction effect resulting in a dense initial metal plasma and metal films which are subsequently being nitrified.

## Fabrication and characterization of a Ni-Mn-Ga uniaxially textured freestanding film deposited by DC magnetron sputtering

Tillier, Jérémy; Bourgault, Daniel; Barbara, Bernard; Pairis, Sébastien; Porcar, Laureline; Chometon, Paul; Dufeu, Didier; Caillault, Nathalie; Carbone, Laurent
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
46.69%
Homogeneous freestanding films have been obtained by the direct current (DC) magnetron sputtering technique using a sacrificial layer. After annealing, the films are crystallized with a strong out-of-plane texture along the (022) direction. The stoichiometry of the annealed films is close to the target composition and leads to a martensitic transformation around 255K. The annealed films demonstrate ferromagnetic behavior with a Curie temperature of about 362K. The magnetization process has been studied on the both states and during the martensitic transition. The saturation magnetizations have been determined by fitting the experimental data with a saturation approach law in the range 1-5T. Results show the saturation magnetization of the martensite is around 10% higher than that of the austenite. A model based on intrinsic magnetic properties of each state allowing the description of the magnetization M=f (H, T) of such polycrystalline films during the martensitic transformation is presented. The mass fraction of martensite inside the austenite phase can be determined using this model. The shape memory effect is analyzed both by scanning electron microscopy and by optical microscopy with in-situ measurement of the resistance temperature dependence.

## High quality MgB2 thin films in-situ grown by dc magnetron sputtering

Vaglio, R.; Maglione, M. G.; Di Capua, R.
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
46.69%
Thin films of the recently discovered magnesium diboride (MgB2) intermetalic superconducting compound have been grown using a magnetron sputtering deposition technique followed by in-situ annealing at 830 C. High quality films were obtained on both sapphire and MgO substrates. The best films showed maximum Tc = 35 K (onset), a transition width of 0.5 K, a residual resistivity ratio up to 1.6, a low temperature critical current density Jc > 1 MA/cm2 and anisotropic critical field with gamma = 2.5 close to the values obtained for single crystals. The preparation technique can be easily scaled to produce large area in-situ films.; Comment: 7 pages, 4 figures

## Optical and magnetic properties of Co-TiO2 sandwich Composite films grown by magnetron sputtering

Liu, Fa-Min; Wang, Tian-Min; Li, J. Q.; Zhou, Y. Q.; Zhang, M. C.
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
46.69%
The transition metal ions doped with TiO2 films are of magnetic properties at room temperatures and have stimulated many scientists to study other properties. The Co-TiO2 sandwich composite films have been recently grown on glass and silicon substrates by using alternately radio frequency reactive and direct current magnetron sputtering. The microstructural properties of these films were characterized with Raman spectra and X-ray photoemission spectra (XPS). It shows an anatase TiO2 containing Co nano-layer. Optical absorption spectra have red shift with Co nano-layer increasing, which originated from the quantum confinement and tunnel effects. Magnetic properties show that the saturation magnetization, remanent magnetic induction and coercivity are about 4.35 emu /g, 1.02 emu/g and 569.6 Oe respectively for 12 nm Co layer between the two TiO2 layers.; Comment: 16 pages, 9 figures Submitted to Journal of Crystal Growth

## Face-centered-cubic titanium in Ti/Al multilayer thin films synthesized by magnetron sputtering technique

Rajagopalan, Ramaseshan; Dasgupta, Arup; Divakar, Ramachandran; Dash, Sitaram; Ravindran, Nithya; Saibaba, Saroja; Tyagi, Ashok Kumar; Bera, Supriya; Manna, Indranil
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
46.69%
Ti/Al multilayer thin films with precise thickness have been deposited using a combination of dc and rf magnetron sputtering techniques. Cross-sectional transmission electron microscopy (TEM) revealed unmixed fifteen parallel and alternate layers of Ti and Al with sharp interfaces, each measuring 27 nm and 15 nm in thickness, respectively. The Ti layer was composed of hcp and fcc phases while the Al layer was fcc. Both x-ray diffraction (XRD) and selected area electron diffraction (SAED) analysis confirmed the identity of these phases. Detection of fcc-Ti in as-deposited the Ti/Al multilayer thin film by XRD established that the fcc-Ti phase is not an artifact of TEM sample preparation, as have been envisaged by some of the previous researchers. The fcc-Ti phase appeared when dual rf guns were used for Ti deposition and the diffraction peak intensity corresponding to fcc phase increased when the gun power was raised. A modified equation of state based thermodynamic analysis confirmed that the formation of hcp phase as opposed to the thermodynamically stable fcc phase of pure Ti is due to crystallite size reduction and not impurity driven.; Comment: 20 pages, 5 figures. Submitted to Journal of Applied Physics

## A new investigation of oxygen flow influence on ITO thin films by magnetron sputtering

Chen, Aqing; Zhu, Kaigui; Zhong, Huicai; Sha, Qingyi; Ge, Guanglu
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
46.69%
ITO thin films were deposited on glass substrates by d.c. magnetron sputtering with varied oxygen flow rates. It was found that the optical absorption decreases and optical absorption edge has blue shifts with the increasing oxygen flow rate. Oxygen vacancy concentration was characterized and analyzed by XPS. It is shown that the oxygen vacancy concentration increases with oxygen flow rates, which is a different observation from the current understanding. The energy band structures associated with different vacancy concentrations of ITO were calculated using the first-principle based on density functional theory. The calculation results show that the increase of oxygen vacancies induces the increase of bands below Fermi level as well as the presence of a second band gap, which accounts for effects of the oxygen vacancies on the blue shifts.

## Spatiotemporal synchronization of drift waves in a magnetron sputtering plasma

Martines, E.; Zuin, M.; Cavazzana, R.; Adámek, J.; Antoni, V.; Serianni, G.; Spolaore, M.; Vianello, N.
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
46.69%
A feedforward scheme is applied for drift waves control in a magnetized magnetron sputtering plasma. A system of driven electrodes collecting electron current in a limited region of the explored plasma is used to interact with unstable drift waves. Drift waves actually appear as electrostatic modes characterized by discrete wavelengths of the order of few centimeters and frequencies of about 100 kHz. The effect of external quasi-periodic, both in time and space, travelling perturbations is studied. Particular emphasis is given to the role played by the phase relation between the natural and the imposed fluctuations. It is observed that it is possible by means of localized electrodes, collecting currents which are negligible with respect to those flowing in the plasma, to transfer energy to one single mode and to reduce that associated to the others. Due to the weakness of the external action, only partial control has been achieved.; Comment: Submitted to Physics of Plasmas

## Particle beam experiments for the investigation of plasma-surface interactions: application to magnetron sputtering and polymer treatment

Corbella, Carles; Grosse-Kreul, Simon; Kreiter, Oliver; Arcos, Teresa de los; Benedikt, Jan; von Keudell, Achim
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
46.69%
A beam experiment is presented to study heterogeneous reactions relevant to plasma-surface interactions. Atom and ion beams are focused onto the sample to expose it to quantified beams of oxygen, nitrogen, hydrogen, noble gas ions and metal vapor. The heterogeneous surface processes are monitored in-situ and in real time by means of a quartz crystal microbalance (QCM) and Fourier transform infrared spectroscopy (FTIR). Two examples illustrate the capabilities of the particle beam setup: oxidation and nitriding of aluminum as a model of target poisoning during reactive magnetron sputtering, and plasma treatment of polymers (PET, PP).; Comment: 30 pages, 10 figures

## Intrinsic electron-doping in nominal "non-doped" superconducting (La,Y)$_2$CuO$_4$ thin films grown by dc magnetron sputtering

Zhao, L.; Wu, G.; Liu, R. H.; Chen, X. H.
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
46.69%
The superconducting nominal "non-doped" $La_{1.85}Y_{0.15}CuO_4$ (LYCO) thin films are successfully prepared by dc magnetron-sputtering and in situ post-annealing in vacuum. The best $T_{C0}$ more than 13K is achieved in the optimal LYCO films with highly pure c-axis oriented T'-type structure. In the normal state, the quasi-quadratic temperature dependence of resistivity, the negative Hall coefficient and effect of oxygen content in the films are quite similar to the typical Ce-doped T'-214 cuprates, suggesting that T'-LYCO shows the electron-doping nature like known n-type cuprates, and is not a band superconductor as proposed previously. The charge carriers are considered to be induced by oxygen deficiency.; Comment: 5 pages, 7 figures

## Composition and morphology of metal-containing diamond-like carbon films obtained by reactive magnetron sputtering

Corbella, C.; Pascual, E.; Oncins, G.; Canal, Cristina; Andújar, J. L.; Bertrán, Enric
Tipo: Artículo Formato: 22195 bytes; application/pdf
ENG
Relevância na Pesquisa
46.69%
6 pages, 5 figures.-- Printed version published Jun 22, 2005.-- Issue title: "EMRS 2004, Symposium J" (Strasbourg, May 24-28, 2004).; The addition of metal atoms within the matrix of diamond-like carbon films leads to the improvement of their mechanical properties. The present paper discusses the relationship between the composition and morphology of metal-containing (W, Nb, Mo, Ti) diamond-like carbon thin films deposited at room temperature by reactive magnetron sputtering from a metal target in an argon and methane atmosphere. Composition was measured either by electron microprobe technique or by X-ray photoelectron spectroscopy and shows a smooth variation with relative methane flow. High relative methane flows lead to a bulk saturation of carbon atoms, which leads to a lack of homogeneity in the films as confirmed by secondary ion mass spectrometry. Cross-section micrographs were observed by transmission electron microscopy and revealed a structure strongly influenced by the metal inserted and its abundance. The surface pattern obtained by scanning electrochemical potential microscopy provided the metallicity distribution. These measurements were completed with atomic force microscopy of the surface. Selected area electron diffraction and X-ray diffraction measurements provided data of the crystalline structure along with nano-crystallite size. High-resolution transmission electron microscopy provided images of these crystallites.; This study was partially supported by the Generalitat de Catalunya (SGR 00078) and the CICYT of Spain (projects MAT 2002-04263-C04 and MAT 2003-02997).; Peer reviewed

## Physical Analysis of VO2 Films Grown by Atomic Layer Deposition and RF Magnetron Sputtering

Tangirala, Madhavi; Zhang, Kai; Nminibapiel, David; Pallem, Venkateswara; Dussarrat, Christian; Cao, Wei; Adam, Thomas N.; Johnson, Corbet S.; Elsayed-Ali, Hani E.; Baumgart, Helmut
Fonte: The Electrochemical Society Publicador: The Electrochemical Society
Tipo: Artigo de Revista Científica
EN_US
Relevância na Pesquisa
46.69%
Publisher's PDF.; Among the many vanadium suboxides and different stoichiometries, VO2 has received considerable attention due to its remarkable metal-insulator transition (MIT) behavior, which causes a significant reversible change in its electrical and optical properties occurring across the phase transition at 67◦C. The initially amorphous VO2 thin films were fabricated by the emerging, Atomic Layer Deposition (ALD) technique with (tetrakis[ethylmethylamino]vanadium) {V(NEtMe)4} as precursor and H2O vapor as oxidation agent. For benchmarking we have also used the RF Magnetron Sputtering technique to deposit metallic vanadium thin films, which were later oxidized during furnace annealing. Post annealing of the as-deposited ALD films was performed in order to obtain the technologically important form of crystallized VO2 thin films using furnace annealing. All film depositions were carried out on native oxide covered (100) Si substrates. The conditions for successful furnace annealing are reported in terms of temperature and annealing gas composition and the physical characterization results are presented.; University of Delaware. College of Engineering.

## Ultraviolet lasing with low excitation intensity in deep-level emission free ZnO films

Wang, Rongping; Muto, H; Gang, X; Jin, P; Tazawa, M
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
46.69%
We have prepared high-quality zinc oxide (ZnO) films by using laser ablation and magnetron sputtering. The deep-level emission free spectra have been obtained for ZnO films on both sapphire and fused silica. It was found that the stimulated emission and band-edge emission were sensitive to the quality of the ZnO films. Strong band-edge emission can be achieved and the stimulated emission can be excited at low threshold excitation density of 7 W/cm 2 in single crystal ZnO films. By using special devised optical geometry, we have proved that the traditional resonant cavity is not imperative to form the lasing and that in-plane closed loop paths via multiple scattering between crystalline grains seems more suitable to account for the lasing mechanism.

## TRIBOLOGY OF ZrN, CrN AND TiAlN THIN FILMS DEPOSITED BY REACTIVE MAGNETRON SPUTTERING

RUDEN,ALEXANDER; GONZÁLEZ,JUAN M.; RESTREPO,JOHANS S.; CANO,MICHELL F.; SEQUEDA,FEDERICO