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Deposition Parameters (deposition + parameter)
Selected AbstractsColloid deposition experiments as a diagnostic tool for biomass attachment onto bioproduct adsorbent surfacesJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 2 2008Canan Tari Abstract BACKGROUND: Detrimental processing conditions can be expected in any downstream operation where direct contacting between a crude feedstock and a reactive solid phase is supposed to occur. In this paper we have investigated the factors influencing intact yeast cells deposition onto anion and cation exchangers currently utilized for expanded-bed adsorption of biotechnological products. The aim of this study was twofold: (a) to confirm previous findings relating biomass deposition with surface energetics according to the extended Derjaguin, Landau, Verwey and Overbeek theory (XDLVO) theory; and (b) to provide a simple experimental tool to evaluate biomass deposition onto process surfaces. RESULTS:Biomass deposition experiments were performed on an automated workstation utilizing a packed-bed format. Two commercial ion exchangers intended for the direct capture of bioproducts in the presence of suspended biological particles were employed. Intact yeast cells in the late exponential phase of growth were selected as model bio-colloids. Cell deposition was systematically evaluated as a function of fluid-phase conductivity and quantitatively expressed as a biomass deposition parameter (,). CONCLUSION: , ,0.15 was established as a criterion to reflect negligible biomass adhesion to the process support(s). Biomass deposition experiments further confirmed predictions made on the basis of free interfacial energy calculations as per the extended DLVO approach. Copyright © 2008 Society of Chemical Industry [source] Preparation of undoped and indium doped ZnO thin films by pulsed laser deposition methodCRYSTAL RESEARCH AND TECHNOLOGY, Issue 12 2005B. Kotlyarchuk Abstract An original modification of the standard Pulse Laser Deposition (PLD) method for preparing both undoped and indium doped zinc oxide (ZnO:In) thin films at low substrate temperature is proposed. This preparation method does not demand any further post-deposition annealing treatment of the grown films. The developed method allows to grow thin films at low substrate temperature that prevents them from the considerable loss of their intrinsic electrical and optical properties. The influence of deposition parameters on the electrical and optical parameters of the undoped and the indium doped ZnO thin films is also analysed. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Abscheidung von Palladium und Palladiumlegierungen mit hohen Schichtdicken für die MikrosystemtechnikMATERIALWISSENSCHAFT UND WERKSTOFFTECHNIK, Issue 2 2007E. Günther Palladium and palladium alloys; Heavy deposits are used; Microsystems technology; Internal stress; Graph of current density vs. potential Abstract Die Abscheidung von Metallen und Legierungen in Mikrostrukturen erfordert meist eine Schichtdicke größer als 100 ,m, die der Strukturhöhe entspricht. Für die Nutzung von Edelmetallen in Mikrosystemen ist die Abscheidung von spannungsarmen, rissfreien, porenfreien und duktilen Schichten notwendig. Da die kommerziell abgeschiedenen Edelmetallschichten nur bis etwa 10 ,m qualitätsgerecht abgeschieden werden können, sind geeignete Zusätze und Variation der Abscheidungsbedingungen erforderlich, um mikrosystemtaugliche Elektrolyte zu entwickeln. Charakterisierung der Schichteigenschaften, Parameter der Abscheidungstechnologie und Anwendungsbeispiele werden aufgeführt. Erste Ergebnisse werden vorgestellt und diskutiert. Deposition of Thick Palladium and Palladium Alloy Layers for Microsystems Technology Layers of metals and alloys deposited in microstructures usually require to be thicker than the 100 ,m which is the approximate height of the structure. The deposited form of noble metals used in microsystems must be non-stressed, ductile and free of cracks and pores. As the thickness of layers deposited from commercial noble metal electrolytes will rarely exceed 10 ,m without loss of quality, developing an electrolyte system suitable for microsystems involves finding appropriate additives and deposition parameters. Details are given of deposit characterisation, the parameters of the deposition technology and some practical examples. Initial results are presented and discussed. [source] Porous silicon/metal nanocomposite with tailored magnetic propertiesPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 6 2009Petra Granitzer Abstract Porous silicon (PS) templates in the meso/macro porous regime with oriented pores clearly separated from each other and filled in a galvanic deposition process with various metals, especially ferromagnetic ones are magnetically investigated. The employment of different metals (e.g. Ni, Co, NiCo) together with the variation of the electrochemical deposition parameters modifies the structural characteristics of the PS/metal nanocomposite and thus leads to distinct magnetic properties of the hybrid system. Furthermore the use of different PS-templates which means a change of the pore-diameter and interpore spacing results also in various magnetic characteristics, especially influences on the magnetic interactions among the deposited metal nanostructures. Therefore the specimens show tailored magnetic properties like coercivity, squareness and magnetic anisotropy. The achieved nanocomposite merges electronic properties of a semiconductor with nanomagnetism and therefore opens the possibility of integrated spin-based electronic devices. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Shape-selective synthesis of II,VI semiconductor nanowiresPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 13 2006A. Fasoli Abstract Polar II,VI semiconductors can nucleate in complex shapes ranging from nanowires to nanoribbons, nanosaws and multipods. Here we demonstrate the deterministic and fully reproducible shape-selective growth of several morphologies of CdSe and ZnTe nanocrystals by a steady-state vapour transport process. A simple pressure-based precursor-flow shutter excludes any effects of temperature ramping, ensuring reproducible shape selectivity for each set of deposition parameters. Once thermal gradients are eliminated, we show that the transition from one nanocrystal shape to another is controlled just by the interplay of precursor impinging on the substrate (ruled by the powder temperature TP) and sample surface kinetics (ruled by the sample temperature TS). Furthermore, a regime is found where seeded, epitaxial growth of CdSe nanorods becomes dominant over the conventional catalyst-assisted nucleation. This allows the fabrication of vertical nanorod arrays free of any metal contamination. Seeded growth of branched and tetrapod-like nanocrystals is also possible by further optimisation of the growth parameters. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Investigation of structural properties of high-rate deposited SiNx films prepared at low temperatures (100,300 °C) by atmospheric-pressure plasma CVDPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 3-4 2010Y. Yamaguchi Abstract We have investigated the structural properties of silicon nitride (SiNx) films deposited at low temperatures (100,300 °C with very high rates (>50 nm/s) in atmospheric-pressure He/H2/SiH4/NH3 plasma excited by a 150 MHz very high-frequency (VHF) power using a cylindrical rotary electrode. For this purpose, SiNx films are prepared on Si(001) wafers varying NH3/SiH4 ratio, H2 concentration in the plasma and substrate temperature (Tsub). Infrared absorption spectroscopy is used to analyze the bonding configurations of Si, N and H atoms in the films. It is shown that by decreasing NH3/SiH4 ratio or increasing H2 concentration, Si,N and Si,H bond densities increase, while N,H bond density decreases. A reasonably good-quality film showing a BHF etching rate of 28 nm/min and a refractive index of 1.81 is obtained at Tsub = 300 °C despite the very high deposition rate of 166 nm/s. However, it is found that the decrease in Tsub causes the deterioration of film quality. Further surface excitation by increasing VHF power and/or H2 concentration together with the optimization of other deposition parameters will be needed to form high-quality SiNx films with high rates at lower temperatures (Tsub , 100 °C). (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Pulsed Nanocomposite TiAlN Coatings on Complex Shaped Tools for High Performance Cutting OperationsPLASMA PROCESSES AND POLYMERS, Issue S1 2007Kirsten Bobzin Abstract The demand on high profitability in cutting operations has led to a variety of requirements for high performance tool coatings. Nanostructured coatings have shown most promising results in this connection. High oxidation resistance, hot hardness, and loW friction are just a few benefits that these coatings offer. The deposition of nanostructured coatings is only possible within a small deposition process window. Most cutting tool surfaces are complex shaped and include, for instance, small corner radii at the cutting edge or chip breakers. The local process window and the deposition parameters must be adapted to the actual shape of the cutting tools in order to obtain a hard nanocomposite coating with adequate adhesion properties. Finally, the performance of these coatings has been studied in machining tests. [source] Study of the Cathode Potential in a Sputtering Discharge by Pulsing the Reactive Gas: Case of a W Target in an Ar-O2 AtmospherePLASMA PROCESSES AND POLYMERS, Issue 1 2007Nuno M.G. Parreira Abstract The process we used was d.c. magnetron sputtering, and we studied both the conventional process, using a constant flow of oxygen, and the process in which we pulsed the reactive gas. Square regulation signal with different pulsing periods (T) and oxygen injection time (ton) was used in the reactive gas pulsing (RGP), while the partial argon pressure was kept constant for all depositions. The oxygen flow rate during the injection time was sufficient to switch the process to compound sputtering mode, while the oxygen flow was stopped in the rest of period to allow cleaning of target. Sputtering experiments have shown that the instability phenomena, typical of the reactive sputtering process and known as the "hysteresis effect", are relatively weak due to the small reactivity of tungsten. The influence of the pulsing period and of the oxygen injection time on the deposition parameters is discussed in relation to the poisoning effect. It has been shown that d.c. magnetron sputtering with the oxygen pulsing is a suitable method to prepare tungsten oxide films. This process is very stable, leads to multilayered W-O coatings, and the deposition rates are slightly lower than those of obtained during the conventional process. [source] High-quality surface passivation of silicon solar cells in an industrial-type inline plasma silicon nitride deposition systemPROGRESS IN PHOTOVOLTAICS: RESEARCH & APPLICATIONS, Issue 1 2004Jens D. Moschner Abstract We have studied the surface passivation of silicon by deposition of silicon nitride (SiN) in an industrial-type inline plasma-enhanced chemical vapor deposition (PECVD) reactor designed for the continuous coating of silicon solar cells with high throughput. An optimization study for the passivation of low-resistivity p -type silicon has been performed exploring the dependence of the film quality on key deposition parameters of the system. With the optimized films, excellent passivation properties have been obtained, both on undiffused p -type silicon and on phosphorus-diffused n+ emitters. Using a simple design, solar cells with conversion efficiencies above 20% have been fabricated to prove the efficacy of the inline PECVD SiN. The passivation properties of the films are on a par with those of high-quality films prepared in small-area laboratory PECVD reactors. Copyright © 2004 John Wiley & Sons, Ltd. [source] 4H SiC Epitaxial Growth with Chlorine AdditionCHEMICAL VAPOR DEPOSITION, Issue 8-9 2006F. La Abstract The growth rate of a 4H-SiC epitaxial layer has been increased by a factor of 19 (up to 112,,m h,1) with respect to the standard process, with the introduction of HCl in the deposition chamber. The epitaxial layers grown with the addition of HCl has been characterized by electrical, optical, and structural characterization methods. The effects of various deposition parameters on the epitaxial growth process have been described, and an explanation of this behavior in terms of the diffusion coefficient on the surface, Ds, and the ratio between the characteristic times, ,D:,G, has been provided. The diodes, manufactured on the epitaxial layer grown with the addition of HCl at 1600,°C, have electrical characteristics comparable with the standard epitaxial process. This process is very promising for high-power devices with a breakdown voltage of 10,kV. [source] Fabrication, Characterisation and Voltammetric Studies of Gold Amalgam Nanoparticle Modified ElectrodesCHEMPHYSCHEM, Issue 9 2004Christine M. Welch Abstract The fabrication, characterisation, and electroanalytical application of gold and gold amalgam nanoparticles on glassy carbon electrodes is examined. Once the deposition parameters for gold nanoparticle electrodes were optimised, the analytical utility of the electrodes was examined in CrIIIelectroanalysis. It was found that gold nanoparticle modified (Au-NM) electrodes possess higher sensitivity than gold macroelectrodes. In addition, gold amalgam nanoparticle modified (AuHg-NM) electrodes were fabricated and characterised. The response of those electrodes was recorded in the presence of important environmental analytes (heavy metal cations). It was found AuHg-NM electrodes demonstrate a unique voltammetric behaviour and can be applied for electroanalysis when enhanced sensitivity is crucial. [source] | ||||||||||||||||