BaCuChF (Ch = S, Se, Te) materials are chalcogen-based transparent conductors with wide optical band gaps (2.9 – 3.5 eV) and a high concentration of free holes (10¹⁸ – 10²⁰ cm⁻³) caused by the presence of copper vacancies. Chalcogen vacancies compensate copper vacancies in these materials, setting the Fermi level...
This dissertation concerns several problems in the fields of light interaction with nanostructured media, metamaterials, and plasmonics. We present a technique capable of extending operational bandwidth of hyperbolic metamaterials based on interleaved highly-doped InGaAs and undoped AlInAs multilayer stacks. The experimental results confirm theoretical predictions, exhibiting broadband negative refraction response...
As electronics reach nanometer size scales, new avenues of integrating biology and electronics become available. For example, nanoscale field-effect transistors have been integrated with single neurons to detect neural activity. Researchers have also used nanoscale materials to build electronic ears and noses. Another exciting development is the use of nanoscale...
The decrease of switching times accompanied by the corresponding increase of
clock speeds and data rates, contributes to improve the overall system
computational performance. At the same time, they also affect wireless
communications due to an increment in the emissions of electromagnetic
radiation on the radio bands.
In this dissertation...
This thesis will cover work that I have completed relating to the field of terahertz (THz) science. My work has consisted of generating tunable, narrowband THz pulses in a table-top optical setup and using both narrow- and broadband THz pulses to study various material systems. Broadband THz pulses were used...
We developed a model to investigate the dielectric properties of the
BaTiO₃ − Bi(Zn₁/₂Ti₁/₂)O₃ (BT-BZT) solid solution, which is a relaxor ferroelectric and exhibits long range disorder. The model uses ab initio methods
to determine all polarization states for every atomic configuration of 2 x 2 x 2
supercells of...
In this thesis, I present studies in the field of terahertz (THz) spectroscopy. These studies are divided into three areas: Development of a narrowband THz source, the study of carrier transport in metal thin films, and the exploration of coherent dynamics of quasi-particles in semiconductor nanostructures with both broadband and...
The optical response of metallic structures is dominated by the dynamics of their free electron plasma. Plasmonics, the area of optics specializing in the electromagnetic behavior of heterogeneous structures with metallic inclusions, is undergoing rapid development, fueled in part by recent progress in experimental fabrication techniques and novel
theoretical approaches....
The increased use of mobile wireless devices that we have recently been witnessing, such as smartphones, tablets, e-readers, and WiFi enabled devices in general, is driving an unprecedented increase in the amount of data traffic. This fast market adoption of the wireless technology along with the tremendous success of multimedia...
Porous media flows are encountered in many natural and man-made systems such as gas adsorption, filtration, heat exchangers, combustion, catalytic reactors and groundwater hydrology. This study experimentally investigates these flows as function of pore Reynolds number, Re[subscript pore]. The pore Reynolds number is based on the porous bed hydraulic diameter,...
This thesis presents the results from Monte Carlo calculations on classical vector spins in
face-centered-cubic (FCC) lattices. The goal of the study was to understand the effect of
interlayer coupling, dilution of magnetic atoms in the lattice, and symmetry-changing
strain.
Experimental work by T. M. Giebultowicz et al. and J....
BiCuOSe and SnS are layered, moderate band gap (ε[subscript G] ≈ 1 eV) semiconductors that exhibit intrinsic p type conductivity. Doping of BiCuOSe with Ca results in a slight expansion of the lattice and an increase of the hole concentration from 10¹⁸ cm⁻³ to greater than 10²⁰ cm⁻³. The large...
The synthesis of axially chiral polyfunctional derivatives of 8,8'-biquinolyl was explored and the catalytic action of appropriate derivative types investigated in three separate processes: (1) the silylcyanation of carbonyl groups and imines, (2) alkylation of a glycine Schiff-base via phase transfer-catalysis, and (3) direct amide bond formation from simple amines...
Proteins are essential to all biological systems. Proteins participate in numerous cellular processes by interacting with other proteins, other metabolites and membranes in a dynamic environment. Studying the structural and conformational properties of proteins in the solution phase is necessary to understand their protein folding and interaction dynamics. This research...
Carbon Nanotubes are a unique family of nanostructures that have shown remarkable promise for mechanical, electrical, and optical applications. Fundamentally similar to the earlier discovered Buckminsterfullerene (C₆₀), carbon nanotubes are hollow cylinders formed from a single sheet of carbon atoms. The research presented in this dissertation investigates several carbon nanotube...
This thesis describes the development of a new enantioselective synthetic method employing chiral cis-2,5-diaminobicyclo[2.2.2]octane-based organometallic catalysts. The significance of this new method to organic synthesis is illustrated with preparation of enantioenriched products that are transformed to important pharmaceutical agents. Chapter 1 provides a brief historical overview of asymmetric catalysis, especially...
Low-dimensional electronic materials offer a platform to observe biological processes with unprecedented spatial and temporal resolution. Carbon nanotubes (CNTs) are the closest physical analog to an ideal 1D system and can be scaled and integrated into multiplexed electronic circuitry. The molecular structure of a CNT is also biocompatible, making them...
The development and some applications of holographic optical tweezers (HOT) are presented. Our HOT system uses a spatial light modulator (SLM) to control the location and properties of the optical trap. We have developed a method for optimizing the diffraction efficiency of a SLM that can be applied in situ...
In this dissertation, a series of studies in the field of terahertz (THz) science are presented, specifically using nonlinear THz spectroscopy. We exploit huge field enhancement and subwavelength confinement in plasmonic structures. There are three distinct projects which will be discussed: nonlinear THz spectroscopy using plasmonic induced transparency (PIT), THz-triggered...
In this dissertation, I describe spectroscopic studies of jet-cooled polycyclic aromatic hydrocarbons (PAH) and one nitrogen substituted PAH (PANH) using pulsed field zero kinetic energy (ZEKE) photoelectron spectroscopy and resonantly enhanced multiphoton ionization (REMPI) spectroscopy. Recently, there has been a demand for far-infrared (FIR) spectral information of astrophysically relevant molecules...
This dissertation is an exploration of the material response to Terahertz (THz) radiation. Specifically we will explore the ultrafast electron dynamics in the nonperturbative regime in semiconductors that have been patterned with nanoantenna arrays using broadband, high intensity, THz radiation. Three main semiconductor materials will be studied in this work....
Due to a lack of grain boundaries, an amorphous metal thin film (AMTF) possesses advantageous mechanical properties and enhanced chemical stability that is potentially useful for thermal inkjet (TIJ) printing applications. The use of an AMTF as a TIJ resistor or cavitation plate could lead to a thinner TIJ cavitation...
CIGS and CdTe based commercial thin-film solar cells (TFSCs) require an absorber thickness greater than 2 µm and 4 µm, respectively, to adequately absorb the solar spectrum. To efficiently extract photoexcited electrons, these TFSCs require relatively defect-free absorbers with high-minority carrier mobility (> 100 cm2V−1s−1) and long lifetime (> 10...
The electrical stability of amorphous indium-gallium-zinc oxide (a-IGZO) thinfilmtransistors (TFTs) is investigated for flat-panel display applications. Althoughproducts incorporating a-IGZO TFT backplanes are already commercially available,e.g., iMac with 5K retina display, technical challenges need to be addressed for nextgenerationapplications, e.g., active-matrix organic light-emitting diode displays.Device stability is one crucial issue. The...
Fluorescence has proven to be a robust and powerful method of analysis in numerous fields: forensics, pharmaceutics, geology, food science, and environmental sciences have all developed a large collection of fluorescence instruments and methods to overcome application-specific challenges. Biological applications saw the same development of a fluorescence toolkit with methods...
The photophysical properties of two-dimensional (2D) layered van der Waals (vdW) materials, and their heterostructures are manifestly distinct from crystalline bulk materials. Recently, the discovery of new 2D vdW materials and strongly-bound interlayer excitons in these materials has created a new branch in nanoscience. As such, there are a number...
CNTs also offer new opportunities to study new science and develop new technology enabled by their strong electron-electron (e-e) interactions. The lack of dielectric screening inherent in nanoscale structures like CNTs leads to strong e-e interactions, which produce unique physical phenomena. In this thesis, we study the effects of strong...
Femtosecond stimulated Raman spectroscopy (FSRS) is a powerful ultrafast technique which can track photoinduced excited state structural events on femtosecond (fs) to picosecond (ps) timescales. In addition to high temporal and spectral resolutions, FSRS provides a broad spectral window from ca. 100—2000 cm-1 for detection, enabling the direct mapping of...
Several topics are presented in this dissertation, each of which has applications to solar cells and photodetectors. First, we discuss the growth of Cu10Te4S13, copper tellurium tetrahedrite. This material has interesting optical properties; it has a large joint density of states at the conduction band maximum and valence band minimum,...
This work explores the synthesis and characterization of the metastable alloys Sn1-xCaxCh (Ch= S, Se) and nitride compounds Zn-W-Mo-N, which have recently been predicted by theorists. Single phase thin films of Sn1-xCaxS are prepared by pulsed laser deposition and radio-frequency magnetron sputtering and of Sn1-xCaxSe are prepared by pulsed laser...
This thesis outlines the development of new elastomeric materials and manufacturing processes for soft robotics. Specifically, this work describes the development of custom material formulations for use in additive manufacturing, additive manufacturing processing techniques for silicone elastomers, and multi-component additive manufacturing techniques. Material synthesis and processing is a gap in...
This dissertation covers my work relating to the application of strong terahertz (THz) radiation to study the nonlinear properties of nano-scale material. It presents experimental and numerical studies on the optical and electronic properties of various material system including single-layer graphene, multi-walled carbon nanotubes (MWCNTs), nanoantenna-patterned gallium arsenide (GaAs) and...
In this dissertation, I describe the experimental investigation of large superfluid helium droplets. The goal and direction of this thesis is to facilitate the use of these droplets as part of our project ss-EDI. The overall scheme of ss-EDI is to dope proteins inside helium droplets and collect a diffraction...
In this dissertation, the process of computational modeling of amorphous oxide materials is studied. Amorphous oxides have random atomic arrangements with no long-range structural order which makes it difficult to study structure-property relationships. Despite the difficulties, amorphous oxides have great uses as semiconductors and dielectrics in thin-film transistors. The ability...
Cell migration is fundamental for physiological processes such as immune re-sponses, wound healing and development. It is also a critical characteristic of metastatic cancer cells. An extensive amount of studies have focused on 2D sub-strates in order to understand the mechanism of cancer metastasis. However, much less is known about...