| The physical characteristics of matter depend on both chemical composition and atomicscale structure. Materials with structure engineered at the atomic scale, or nanomaterials, differ markedly from bulk solids, and are believed to be the answer in the ongoing quest for materials with superior properties. With properties critically determined by the nanostructure, future advances hinge on developing an understanding of the growth processes and, particularly, on the ability to control and manipulate these processes. This thesis describes a number of advanced nanostructured infrared photonic devices with designable response characteristics, fabricated from vacuum evaporated amorphous silicon with the technique of glancing angle deposition. The technique enables continuous, controlled variation of the refractive index by introducing nanometer-scale oscillations of porosity of the material, thus allowing the manufacture of inhomogeneous photonic coatings such as rugate filters, graded-index broadband anti-reflection coatings and photonic crystals. In addition the thesis presents research that relates to the understanding of growth of glancing angle deposited thin films ranging from sub-nanometer to micron thickness. A number of experimental and analysis techniques used to study the films are described including scanning electron microscopy, atomic force microscopy, Monte Carlo simulations and both in situ and ex situ spectroscopic ellipsometry. The information obtained from this work is not only of fundamental importance but may ultimately lead to the ability to precisely engineer the behaviour and properties of materials of technological potential in the photonics industry. |
