Fabrication of novel core-shell nanostructures for photonics applications

Ankara : Materials Science and Nanotechnology Program of the Graduate School of Engineering and Science of Bilkent Univ., 2013. ; Thesis (Ph. D.) -- Bilkent University, 2013 ; Includes bibliographical references leaves 169-182. ; Developments in nanoscale fabrication and characterization techniques have led to fundamental changes in the scientific understanding of many fields, and novel nanostructures have been utilized to investigate the conceptual underpinnings behind a diverse array of natural phenomena. However, nanofabrication methods are frequently hindered by issues such as misalignment, small batch sizes, high production costs and constraints in material choice or nanostructure diversity, which decrease their potential utility and prevent their widespread application in nanoscale optics and photonics. In this work, a new top-down nanofabrication method is described, which is called Iterative Size Reduction (ISR), where step-by-step reduction is utilized to decrease structure dimensions from macro- to nanosizes and produce indefinitely long one-dimensional core-shell nanostructures with properties highly suitable for use in optical applications. Plateau-Rayleigh instabilities are then utilized to thermally degrade ISR-produced nanowire arrays into complex core-shell schemes, which are produced successively in a hitherto-undescribed transitory region between core-shell nanowires and core-shell nanospheres. A diverse array of optical phenomena have been observed on fabricated novel core-shell nano-platforms, which are utilized in the design of novel nanostructures for emerging photonics applications. Briefly, (a) the resonant Mie scattering behavior is characterized on glass-polymer nanostructures and these nanostructures are designed for large-area structural coloration, (b) a novel non-resonant Mie scattering regime responsible for the scattering characteristics exhibited by all-polymer core-shell nanowires is described, (c) a nanoscale analogue to the thin film interference phenomenon is demonstrated ...