The effect of a magnetic field on copper electrodeposition was investigated. Copper was electrodeposited onto square copper cathodes 1 sq cm in area from an aqueous solution (0.5 M CuSO4, 0.5 M H2SO. A glass cell was placed between the pole pieces of an electromagnet, and the magnetic fields applied were in the range from 0 to 12.5 kG. The current density was in the range from 80 mA/sq cm to 880 mA/sq cm. In each of the experiments, cell current, cell voltage, and cell temperature were monitored with a microcomputer. The weight change, deposit surface and cross section morphology, and the hardness were also found. Anodes used in the experiments were studied to see the effect of various conditions on the surface finish. Copper was also electrodeposited onto copper grids in order to study how the uniformity of the deposit is affected by an applied magnetic field.

Purpose of this work is to provide a comprehensive picture of thin film (interconnect) and solid droplet surface evolution under the several external applied forces with anisotropic physical properties so that one can eventually be able to predict main reasons and conditions under which stability of surface is defined. A systematic study based on the self-consistent dynamical simulations is presented for the spontaneous surface evolution of an thin film and isolated thin solid droplet on a rigid substrate, which is driven by the surface drift diffusion induced by the anisotropic diffusivity, the anisotropic capillary forces (surface stiffness) and mismatch stresses under electron winding. The effect of surface free energy anisotropies (weak and strong (anomalous)) on the development kinetics of the Stranski-Krastanow island type morphology are studied. Although, various tilt angles and anisotropy constants were considered during simulations, the main emphasis was given on the effect of rotational symmetries associated with the surface Helmholtz free energy topography in 2D space. The investigations of dynamics of surface roughness on concurrent actions of the appliedelasto- and electro- static fields clearly indicate that applied misfit stress level is highly important effect on resultant surface form which may be smooth wave like or crack like. The droplet simulations revealed the formation of an extremely thin wetting layer during the development of the bell-shaped Stranski-Krastanow island through the mass accumulation at the central region of the droplet via surface drift-diffusion. The developments in the peak height, in the extension of in the wetting layer beyond the domain boundaries, and the change in triple junction contact angle, one clearly observes that these quantities are reaching certain saturation limits or plateaus, when the growth mode turned-off. Islanding differences for weak anisotropy constant levels and the strong (anomalous) anisotropy constant domains are discussed.

This thesis describes the comparison of time-lapse field observations of suncups on alpine snow with numerical simulations. The simulations consist of solutions to a nonlinear partial differential equation which exhibits spontaneous pattern formation from a low amplitude, random initial surface. Both the field observations and the numerical solutions are found to saturate at a characteristic height and fluctuate chaotically with time. The timescale of these fluctuations is found to be instrumental in determining the full set of parameters for the numerical model such that it mimics the nonlinear dynamics of suncups. These parameters in turn are related to the change in albedo of the snow surface caused by the presence of suncups. This suggests the more general importance of dynamical behaviour in gaining an understanding of pattern formation phenomena.

This thesis describes the comparison of time-lapse field observations of suncups on alpine snow with numerical simulations. The simulations consist of solutions to a nonlinear partial differential equation which exhibits spontaneous pattern formation from a low amplitude, random initial surface. Both the field observations and the numerical solutions are found to saturate at a characteristic height and fluctuate chaotically with time. The timescale of these fluctuations is found to be instrumental in determining the full set of parameters for the numerical model such that it mimics the nonlinear dynamics of suncups. These parameters in turn are related to the change in albedo of the snow surface caused by the presence of suncups. This suggests the more general importance of dynamical behaviour in gaining an understanding of pattern formation phenomena.

Abstract In this work, phase structure and the surface morphology effects on the optical properties of nonlinear active nanocrystalline PZT thin films, with the high refractive index (n ≈ 2.5), were studied. A preliminary thickness-temperature map of the majority phase was presented, showing the dependence of room temperature deposited films thickness and post-annealing temperature on the crystallization and surface morphology. Changes in structural phase and surface morphology were found to define the optical properties of the films. The optical absorption edge shifted to shorter wavelengths with decreasing film thickness and post-annealing temperature, which led to an increase in band gap energies with ΔEg ≈ 0.55eV. Structural phase evolution induced surface effects caused the definite diffuse elements in the transmission spectra of the films. Low and evenly distributed scattering amplitudes in k-space were seen for single-phase oriented films with non-textured surfaces and led to low diffuse transmission values with TD ≈ 5%. Confined and increased scattering amplitudes in k-space were seen for films with phase co-existence, leading to microstructure-induced textured surfaces and increased diffuse transmission values with TD ≈ 50%. Diffuse transmission properties of the films were also calculated from surface profile data, using scalar scattering theory. The results showed very good agreement with the experimentally defined values. The difference between modelled and measured values was 3.8% at the maximum. Also changes in the surface morphology and crystal orientation were found to modulate the full width at half maximum Δβ values of the TE0 optical mode, indicating a strong dependence on the surface scattering process. Sharp optical mode widths Δβ ≈ 0.0048 and Δβ ≈ 0.0006, for single-phase oriented and amorphous-like films, respectively, were found. / Tiivistelmä Tässä työssä tutkittiin nanokiteisten korkean taitekertoimen (n ≈ 2.5) omaavien PZT ohutkalvojen optisten ominaisuuksien riippuvuutta ohutkalvon faasirakenteesta ja pinnan morfologiasta. Rakenneanalyysien perusteella muodostettiin paksuus-lämpötila faasikartta havainnollistamaan jälkihehkutuslämpötilan ja kalvon paksuuden vaikutuksia huoneenlämpötilassa pulssilaserkasvatusmenetelmällä kasvatettujen ohutkalvojen faasirakenteen ja pinnan morfologian muokkautumiseen. Muutokset kalvon faasirakenteessa ja pinnan morfologiassa määrittivät täysin kalvon optiset ominaisuudet siten, että optinen absorptioreuna siirtyi alemmille aallonpituuksille kalvon paksuuden ja jälkihehkutuslämpötilan pienentyessä, aiheuttaen energiaraon kasvun (ΔEg ≈ 0.55 eV). Faasirakenteen indusoiman pinnan morfologian muokkautuminen määritteli myös ohutkalvon sirontaspektrin yksityiskohdat aaltolukuavaruudessa. Tasaisesti jakautunut pienen amplitudin omaava sirontaspektri ja alhainen diffuusi sironta (TD ≈ 5 %) oli ominaista yksifaasisille, voimakkaasti orientoituneille ohutkalvoille, kun taas alhaisille aaltolukuarvoille rajoittunut korkean amplitudin omaava sirontaspektri ja lisääntynyt diffuusi sironta (TD ≈ 50 %) oli ominaista kaksifaasisille ohutkalvoille. Tutkittujen ohutkalvojen sirontaspektrin diffuusi komponentti laskettiin myös käyttäen skalaaria sirontateoriaa. Ero laskettujen ja mitattujen arvojen välillä oli maksimissaan 3.8 %. Muutokset ohutkalvojen pinnan morfologiassa ja faasirakenteessa havaittiin myös moduloivan optisen TE0 moodin puoliarvoleveyttä. Alhaisimmat pouoliarvoleveydet havaittiin yksifaasisilla (Δβ ≈ 0.0048) ja amorfisenkaltaisilla ohutkalvoilla (Δβ ≈ 0.0006).

This thesis describes the comparison of time-lapse field observations of suncups on alpine snow with numerical simulations. The simulations consist of solutions to a nonlinear partial differential equation which exhibits spontaneous pattern formation from a low amplitude, random initial surface. Both the field observations and the numerical solutions are found to saturate at a characteristic height and fluctuate chaotically with time. The timescale of these fluctuations is found to be instrumental in determining the full set of parameters for the numerical model such that it mimics the nonlinear dynamics of suncups. These parameters in turn are related to the change in albedo of the snow surface caused by the presence of suncups. This suggests the more general importance of dynamical behaviour in gaining an understanding of pattern formation phenomena. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

Silicon photonics is emerging as a potential field to achieve optical interconnects towards the realization of ultra high bandwidth. The indirect band-gap property of silicon still remains as a big challenge to incorporate silicon photonic active device, for example, silicon-based laser. In the Laboratory of Semiconductor Materials at KTH, a monolithic integration platform based on nano-epitaxial lateral overgrowth (nano-ELOG) technique has been proposed to integrate III-V semiconductor materials with silicon for light source application. The integration process involves uneven surface morphology at different stages. The surfaces of the indium phosphide seed layer on silicon used for ELOG, the mask deposited on it (the silicon/silicon dioxide waveguide) and the ELOG indium phosphide layer grown on it prior to laser growth are often rough. In this thesis work, we have optimized chemical mechanical polishing (CMP) technique in order to achieve an even surface. The same procedure is also necessary to reach the optimal thickness of different layers to enable effective coupling of light from the laser source into the waveguide. CMP of indium phosphide to obtain an average surface roughness of < 1 nm has been optimized by a two-step polishing using different slurries; it results in a step height of ca 3 nm. Similarly the surface of silicon/silicon dioxide “waveguide” has also been optimized with the roughness of ~ 0.5 nm. In the latter case, a step height of 40 nm is retained and this increase with respect to InP is identified to be mainly due to limitations of the polishing machine which is different from that used for indium phosphide. The reduction in step heights with polishing time is analyzed and compared with an existing theoretical model. Our results are in good qualitative agreement with the model. The optimized surface morphology obtained in this work was tested for its suitability for integration. For this evaluation, InP was grown by ELOG in a hydride vapour phase epitaxy reactor with and without CMP of the involved surfaces. The surface after CMP yields layers of better surface morphology with fewer defects as revealed by atomic force microscopy, surface profilometer and cathodoluminescence analysis. The results indicate that the CMP process is useful for monolithic integration for silicon photonics.

No description available.

Yes / The principal aim of this paper is to investigate the effect of sand grading, surface morphology, and content on the rheological properties—that is, yield stress and plastic viscosity—of fresh mortar. Mortars were produced from four different types of sand at two volumetric cement-sand ratios of 1/0.9 and 1/0.6. Each blend was prepared with five water-cement ratios of 0.60, 0.55, 0.50, 0.45, and 0.40. The rheometer was used to determine yield stress and plastic viscosity parameters of each cement paste and mortar. Test results show that the relative yield stress and plastic viscosity of mortar to cement paste is inversely proportional to the excess paste thickness up to low values, below which the surface texture of sand particles becomes significant.

Neste trabalho otimizou-se uma metodologia para a deposição de filmes de polianilina, PAni, na qual o substrato de vidro é inserido na solução em que se realiza a polimerização. Este método de deposição \"in situ\", feito a temperatura de O &#176C, permite obter filmes com boa uniformidade e com controle de espessura. A espessura dos filmes, da ordem de centenas de nanômetros, pode ser controlada através da concentração da solução do meio reacional. A morfologia da superfície do filme foi estudada usando a técnica de microscopia de força atômica. Os resultados mostraram que a rugosidade aumenta com a diminuição da concentração e com o tempo de deposição da camada de PAni. Para demonstrar a aplicação dos filmes de PAni foi construído um dispositivo eletroluminescente tendo o poli(-fenileno vinileno)-dodecilbenzeno sulfonato de sódio, PPV-DBS, como polímero ativo e usando uma camada de PAni como eletrodo injetor de buracos e janela transparente para a saída da luz. Mostrou-se que o dispositivo opera com uma tensão aproximadamente 3 vezes menor em comparação com um dispositivo sem a camada de PAni. / A method for deposition of polyaniline, PAni, onto glass substrates was studied. Substrates were inserted in the solution in which the polymerization reaction occurs. This method performed \"in situ\", at the temperature of 0 &#176C, gives very uniform films and allows the control of the thickness. Thickness, of the order of hundred nm, can be controlled varying the concentration of the solution in which the polymerization occurs. The morphology of the PAni layer was studied using a force atomic microscope, AFM. The roughness increased on the time of deposition of the layer and with the decrease of the concentration of the solution. In order to demonstrate the use of the PAni layer an electro luminescent device was built using as active polymer poly(-fenylene vinylene) -dodecilbenzene sulphonate of sodium, PPV-DVS, and the PAni layer as injector of holes and was transparent window for the emitted light. The device showed that it could be operated with a voltage that is three times smaller than a corresponding device without the PAni layer.