Island growth and step instabilities on flat and vicinal surfaces

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dc.contributor Aalto-yliopisto fi
dc.contributor Aalto University en Rusanen, Marko 2012-01-24T14:38:47Z 2012-01-24T14:38:47Z 2003-02-26
dc.identifier.isbn 951-22-6374-2
dc.identifier.issn 1455-1802
dc.description.abstract Surface physics aims at understanding the basic atomistic processes and mechanisms responsible for the variety of observed structures during surface growth. In addition, surface growth has important consequences in modern technological applications. Molecular beam epitaxy (MBE) is an established method to grow surface structures, admitting also modeling surface growth through simple microscopic processes such as diffusion and deposition of atoms. The rather limited parameter range in MBE where smooth layer-by-layer growth is realized can be extended, e.g., with ion assisted deposition techniques. Thus new microscopic processes are added to traditional MBE growth. Customarily island growth and step-flow are treated as separate growth modes. Consequently, there does not exist a growth model which includes all relevant aspects of surface growth in a realistic way. The aim of this thesis is to bridge the gap between these traditional approaches. Including other microscopic processes in addition to deposition and surface diffusion introduces new scaling relations and length scales. In addition, not only the scaling of the growth structures but also their stability is of importance. Moreover, unstable growth often possesses a dynamically selected length scale. It is of interest to understand the behavior of these new time and length scales and their scaling properties when constructing more realistic growth models. To this end, we consider various aspects of surface growth. First, we simulate island growth with aggregation, fragmentation, and deposition on flat surfaces. The generalized rate equations are introduced, and the scaling forms for the island size distributions and the mean island size are proposed and compared with simulation results. Next, stability of circular islands is studied by generalizing the rectangular case to radial geometry. A stability criterion for the island radius is derived in the long wavelength limit. Then, stability of step edges on vicinal surfaces is considered. The simulation results demonstrate the dynamical wavelength selection with a quantitative prediction for the selected wavelength as well as the mechanism behind the instability. The average shape of the unstable step patterns is found to have an invariant form, insensitive to the parameters of the model. Finally, the simulations extended to include both island growth and step edge instability reveal that these growth modes are coupled with a new length scale, and are inpendent only in the submonolayer regime. en
dc.format.extent 62, [30]
dc.format.mimetype application/pdf
dc.language.iso en en
dc.publisher Helsinki University of Technology en
dc.publisher Teknillinen korkeakoulu fi
dc.relation.ispartofseries Dissertations / Laboratory of Physics, Helsinki University of Technology en
dc.relation.ispartofseries 120 en
dc.relation.haspart Koponen, I., Rusanen, M. and Heinonen, J., 1998. Island size distributions in submonolayer growth with mobile islands and breakup. Physical Review E 58, pages 4037-4040.
dc.relation.haspart Rusanen, M., Koponen, I. T. and Ala-Nissila, T., 2002. Meandering instability of curved step edges on growth of a crystalline cone. Surface Science 507-510, pages 305-310. [article2.pdf] © 2002 Elsevier Science. By permission.
dc.relation.haspart Rusanen, M., Koponen, I. T., Heinonen, J. and Ala-Nissila, T., 2001. Instability and wavelength selection during step flow growth of metal surfaces vicinal to fcc(001). Physical Review Letters 86, pages 5317-5320.
dc.relation.haspart Rusanen, M., Koponen, I. T., Ala-Nissila, T., Ghosh, C. and Rahman, T. S., 2002. Morphology of ledge patterns during step flow growth of metal surfaces vicinal to fcc(001). Physical Review B 65, pages 041404 : 1-4.
dc.relation.haspart Rusanen, M., Koponen, I. T. and Kallunki, J., 2002. Mixing length scales: step meandering and island nucleation on vicinal surfaces. Submitted to Surface Science (7 pages).
dc.subject.other Physics en
dc.title Island growth and step instabilities on flat and vicinal surfaces en
dc.type G5 Artikkeliväitöskirja fi
dc.description.version reviewed en
dc.contributor.department Department of Engineering Physics and Mathematics en
dc.contributor.department Teknillisen fysiikan ja matematiikan osasto fi
dc.subject.keyword surface growth en
dc.subject.keyword growth instabilities en
dc.subject.keyword pattern formation en
dc.subject.keyword Monte Carlo simulations en
dc.identifier.urn urn:nbn:fi:tkk-000293
dc.type.dcmitype text en
dc.type.ontasot Väitöskirja (artikkeli) fi
dc.type.ontasot Doctoral dissertation (article-based) en
dc.contributor.lab Laboratory of Physics en
dc.contributor.lab Fysiikan laboratorio fi

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