Despite near unanimous opinion on the consequences of climate change by scientific community, the rate at which carbon is emitted into the atmosphere continues to increase. The need for a clean and sustainable source of energy is therefore one of humankind's most urgent challenges. Solar energy is the most abundant...
Physicists who study semiconductor devices are fascinated by the fundamental limits of device performance. From the sub-threshold swing of transistors to the power conversion efficiency of photocells, performance is limited by the electronic structure of the materials used to build them. To surpass traditional device limits, we must turn to...
This dissertation demonstrated that the electrical properties of complex oxide-based perovskite materials could be controlled through the careful modification of both material composition and structure. This was first shown through the modification of lead zirconate titanate (Pb(Zr0.52Ti0.48)O3, PZT) solid solutions with bismuth indate (BiInO3, BI) where the relative stability of...
Transparent conductive oxides (TCOs), such as indium-tin oxide (ITO), have attracted increasing interests in integrated photonics and nanophotonics, owing to their large plasma dispersion and epsilon-near-zero (ENZ) effect. The refractive index modulation induced by free carriers in TCOs leads to a large electro-optic effect that can enable ultra-compact device footprint...
Chemistry of preparing dense film from solution deposition is explored with several cases in this thesis. Surface dense structure, conversion at melting point, and ion exchange in aqueous solution are the main topics covered here for the thin films of aluminum oxide phosphate and tin dioxide. Thin film density, optical...
The overall concept of reducing laboratory operations to a scale that fits on a single microfluidic chip has been an attractive area of research over the last several decades. Despite a surge in research, few commercial success stories have been written. Lab-on-a-chip technologies have the capability to be cost effective...
This dissertation focuses on the development of ultra-compact optical devices for free-space modulation. We propose a surface-normal modulator using metallic photonic crystals for free-space optical interconnects. The active control of light intensity is achieved by engineering the Fano resonances in metallic photonic crystals. Both thermo-optic modulation and electro-optic modulation of...
Aerogels are interesting material systems with outstanding properties such as low density, high surface area, and low thermal conductivity. They can be used for a variety of applications, such as solar cells, sensors, or catalysts. Additionally they provide a unique model system to study the properties of small particles. Cellulose...
The role of A-site non-stoichiometry was investigated in lead-free piezoelectric ceramics based on compositions in the 1-x(Bi₀.₅Na₀.₅TiO₃)-xBaTiO₃ system near the morphotropic phase boundary where x = 0.055, 0.06 and 0.07. The samples were prepared by a conventional solid state mixed oxide route with the A- site stoichiometry modified to incorporate...
The objective of the research presented herein is to elucidate the effect of traps in determining amorphous oxide semiconductor thin-film transistor (AOS TFT) performance using modeling and characterization. A novel method is proposed to extract the interface state distribution from a TFT transfer curve. Analysis of zinc-indium oxide (ZIO), zinc-tin...