Shape-preserving physical and chemical transformations of Si and SiO₂ nano- and microstructures

• Main Author: Gordin, Ari
• Other Authors: Sandhage, Kenneth
• Format: Others
• Language: en_US
• Published: Georgia Institute of Technology 2015
• Subjects: Shape-preserving transformations; Photonics
• Online Access: http://hdl.handle.net/1853/54026

This thesis considers two broad categories of shape-preserving transformations: physical transformations, in which the chemistry of the as-grown material remains constant but some structural change is introduced (i.e., conversion of dense silicon nanowires into porous silicon nanowires); and chemical transformations, in which the physical structure of the as-grown material remains constant but the chemical composition is changed (i.e., conversion of SiO2 photonic crystal fibers into MgF¬2 photonic crystal fibers). Part I of this thesis focuses on the development of a process which allows for the introduction of porosity into dense silicon nano- and microstructures (a shape preserving net physical transformation, albeit by chemical means), while Part II focuses on conversion of SiO2-based photonic structures, including three dimensional photonic crystals and hollow-core photonic crystal fibers into Mg2Si or MgF2 replicas with more desirable chemical compositions (a shape preserving net chemical transformation) possessing enhanced optical characteristics.