Structural and Surface Transformations in Complex Nanostructures: A Basic Science Approach Towards Controlled Nanoscale Engineering Nicola Ferralis DA 114 Fri 6 November 2009 10:30 AMPhysics ColloquiumThe characterization of the growth mechanisms of nanostructures often relies on the understanding of the basic and fundamental surface and interface phenomena taking place during the process. Here, I will present two cases in which such understanding is successfully achieved by direct investigations of the surface and interface structural transformations and dynamics at the surface of nanostructures: controlled hierarchical branching of silicon nanowires, and strain control in epitaxial graphene. In the first case, I will describe a novel in-situ and real-time investigation of the spreading dynamics of a single layer of gold atoms from large self-pinned gold reservoirs flat Si surfaces. The gained understanding of the reactive, non-diffusive nature of the spreading process is used for nanoscale control of a self-seeding growth of branches in nanowires via vapor-liquid-solid mechanism. In the second case, I will describe how the substrate-induced strain in epitaxial graphene grown on SiC surfaces are strongly affected by optimized synthesis conditions. A comprehensive description of the temperature dependent evolution of the epigraphene morphology and the competing graphene-substrate interactions will be provided. The implications of this fundamental investigation to nanoscale strain engineering will be discussed.