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The effect of deposition conditions on the properties of RF sputtered silicon filmsQudah, Ali M. A. January 1990 (has links)
No description available.
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Morphological imperfections associated with molecular beam epitaxial growth of GaAs layersKadhim, N. J. January 1987 (has links)
No description available.
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Microstructural studies of the formation of titanium silicideStephenson, Andrew William January 1993 (has links)
No description available.
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Structure and properties of metallic overlayers on Ru(100)Poulston, Stephen January 1994 (has links)
No description available.
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Surface magnetism of Fe/Si(111) and Fe/Si(100)Nazir, Z. H. January 1997 (has links)
No description available.
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Nanoscale resonators fabricated from metallic alloys, and modeling and simulation of polycrystalline thin film growthOphus, Colin L 06 1900 (has links)
Part I - We have designed a binary metallic alloy for nanoscale resonator applications. We used magnetron sputtering to deposit films with different stoichiometries of aluminum and molybdenum and then characterized the microstructure and physical properties of each film. A structure zone map is proposed to describe the dependence of surface and bulk structure on composition. We then fabricated proof of principle resonators from the Al-32 at%Mo composition, selected for its optimized physical properties. An optical interferometer was used to characterize the frequency response of our resonators.
Part II - We investigate the growth of faceted polycrystalline thin films with modeling and simulations. A new analytic model is derived for the case of orientation dependent facet growth velocity and the dependence of growth on initial grain orientations is explicitly calculated. Level set simulations were used to both confirm this analytic model and extend it to include various angular flux distributions, corresponding to different deposition methods. From these simulations, the effects of self-shadowing on polycrystalline film growth are quantitatively evaluated. / Materials Engineering
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Antimicrobial Activity of Cationic Antiseptics in Layer-by-Layer Thin Film AssembliesDvoracek, Charlene M. 2009 May 1900 (has links)
Layer-by-layer (LbL) assembly has proven to be a powerful technique for
assembling thin films with a variety of properties including electrochromic, molecular
sensing, oxygen barrier, and antimicrobial. LbL involves the deposition of alternating
cationic and anionic ingredients from solution, utilizing the electrostatic charges to
develop multilayer films. The present work incorporates cationic antimicrobial agents
into the positively-charged layers of LbL assemblies. When these thin films are exposed
to a humid environment, the antimicrobial molecules readily diffuse out and prevent
bacterial growth. The influence of exposure time, testing temperature, secondary
ingredients and number of bilayers on antimicrobial efficacy is evaluated here.
Additionally, film growth and microstructure are analyzed to better understand the
behavior of these films.
The antimicrobial used here is a positively-charged quaternary ammonium
molecule (e.g. cetyltrimethylammonium bromide [CTAB]) that allow assemblies to be
made with or without an additional polycation like polydiallyldimethylamine. While
films without this additional polymer are effective, they do not have the longevity or uniformity of films prepared with its addition. All of the recipes studied show linear
growth as a function of the number of bilayers deposited and this growth is relatively
thick (i.e. > 100 nm per bilayer). In general, 10-bilayer films prepared with CTAB and
poly(acrylic acid) are able to achieve a 2.3 mm zone of inhibition against S. aureus
bacteria and 1.3 mm against E. coli when test are conducted at body temperature (i.e.
37oC). Fewer bilayers reduces efficacy, but lower test temperatures improve zones of
inhibition. As long as they are stored in a dry atmosphere, antimicrobial efficacy was
found to persist even when films were used four weeks after being prepared. The best
films remain effective (i.e. antimicrobially active) for 4-6 days of constant exposure to
bacteria-swabbed plates. This technology holds promise for use in transparent wound
bandages and temporary surface sterilization.
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Nanoscale resonators fabricated from metallic alloys, and modeling and simulation of polycrystalline thin film growthOphus, Colin L Unknown Date
No description available.
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GPU Enhanced Simulations of Glancing Angle Deposition of Metal Thin-FilmsLiu, Xuejing 09 July 2012 (has links)
No description available.
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Molecular dynamics simulations of multiple Ag nanoclusters deposition on a substrateBoumerdassi, Nawel 09 October 2014 (has links)
Ag thin and thick films have been experimentally deposited using a technique called Laser Ablation of a Microparticle Aerosol (LAMA). This technique is based on a supersonic jet accelerating NPs of a few nm diameter up to 1000 m/s and operating at room temperature. The deposited films have experimentally demonstrated interesting properties such as dense growth with good adherence on the substrate. Aerosol feed rates have been fixed to 10 mg/h which corresponds to rate depositions of 10¹⁰ to 10¹¹ NPs/s/cm². In order to model this deposition technique and possibly be able to predict the morphology and structure of deposited films using computational methods, we have designed MD programs simulating the depositions of several Ag nanoclusters onto a substrate at a fixed temperature (300 K). The variation of parameters such as cluster size, cluster impact energy, and deposition rate has influenced the morphology and structure of the deposited films. Cluster diameters have been set to 3 nm or 5 nm, cluster velocities set to 200 m/s (0.022 eV/atom), 400 m/s (0.069 eV/ atom), or 800 m/s (0.358 eV/atom), and the deposition rate adjusted to ensure relaxation times between impactions of 5 ps to 20 ps. The evolution of deposited film density, adherence, and crystal arrangement has been analyzed with the variation of the aforementioned parameters. The highest cluster velocities have enabled the deposition of smoother, denser, and more adherent films. NCs with an initial velocity of 200 m/s have shown ratios of flattening equal to 50 % as opposed to 85% flattening for NCs deposited at 800 m/s. These observations have enabled us to draw qualitative conclusions on the film density The deposited films are less porous when the cluster impaction velocity increases. Atomic mixing between substrate and impacted NC atoms increased with increasing deposition velocity, which can perhaps be correlated to an increase of adherence, assuming that more mixing will create stronger molecular binding in the cluster-substrate interaction. Finally, complete epitaxial growth was observed for the highest impaction velocities only, which indicates that recrystalization can occur for this range of impact energies (0.3 eV/atom - 0.5 eV/atom). Although experimental results have given more quantitative data on film density and sticking ratios, they agree with our modeling, and this comparison allows us to validate our MD simulations. However, some limitations have been faced, mainly because of long computing time requirements that a single laptop computer has not been able to support. / text
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