Nanoscience and Nanotechnology Commons^™

Measuring Nonlinear Properties Of Graphene Thin Films Using Z-Scan Technique, Thekrayat Hassan Al Abdulaal

Graduate Theses and Dissertations

The nonlinear studies of two-dimensional (2D) nanomaterials, specifically graphene, are very significant since graphene is finding its usefulness in handling the enormous heat in nanoscale high-density power electronics. Graphene has emerged to be a promising nanomaterial as an excellent heat spreader due to its high thermal conductivity. However, the experimental nonlinear study of graphene materials and their application in developing future optoelectronic devices demands for more developed research.

The research objective is first to build a precise, and sensitive technique to investigate and understand the thermal nonlinear properties, including nonlinear refractive index (n2), nonlinear absorption coefficient (β), and thermo-optic coefficient …

Synthesis, Characterization, And Fabrication Of All Inorganic Quantum Dot Leds, Haider Baqer Salman

Graduate Theses and Dissertations

Quantum Dot LEDs with all inorganic materials are investigated in this thesis. The research was motivated by the potential disruptive technology of core shell quantum dots in lighting and display applications. These devices consisted of three main layers: hole transport layer (HTL), electron transport layer (ETL), and emissive layer where the emission of photons occurs. The latter part was formed of CdSe / ZnS core-shell quantum dots, which were synthesized following hot injection method. The ETL and the HTL were formed of zinc oxide nanocrystals and nickel oxide, respectively. Motivated by the low cost synthesis and deposition, NiO and ZnO …

Coarse-Grained Simulations Of The Self-Assembly Of Dna-Linked Gold Nanoparticle Building Blocks, Charles Wrightsman Armistead

Graduate Theses and Dissertations

The self-assembly of nanoparticles (NPs) of varying shape, size, and composition for the purpose of constructing useful nanoassemblies with tailored properties remains challenging. Although progress has been made to design anisotropic building blocks that exhibit the required control for the precise placement of various NPs within a defined arrangement, there still exists obstacles in the technology to maximize the programmability in the self-assembly of NP building blocks. Currently, the self-assembly of nanostructures involves much experimental trial and error. Computational modeling is a possible approach that could be utilized to facilitate the purposeful design of the self-assembly of NP building blocks …

Interactive Physics And Characteristics Of Photons And Photoelectrons In Hyperbranched Zinc Oxide Nanostructures, Garrett Edward Torix

Graduate Theses and Dissertations

As is commonly known, the world is full of technological wonders, where a multitude of electronic devices and instruments continuously help push the boundaries of scientific knowledge and discovery. These new devices and instruments of science must be utilized at peak efficiency in order to benefit humanity with the most advanced scientific knowledge. In order to attain this level of efficiency, the materials which make up these electronics, or possibly more important, the fundamental characteristics of these materials, must be fully understood. The following research attempted to uncover the properties and characteristics of a selected family of materials. Herein, zinc …

A Bifunctional Nanocomposites Based Electrochemical Biosensor For In-Field Detection Of Pathogenic Bacteria In Food, Meng Xu

Graduate Theses and Dissertations

This research focused on the application of electrochemical biosensors for the rapid detection of pathogenic bacteria, Escherichia coli O157:H7 and Salmonella Typhimurium, in foods. The possible presence of pathogenic bacteria in foods has always been a great threat to the wellbeing of people and the revenue of food companies. Therefore, the demand for rapid and sensitive methods to detect foodborne pathogens is growing. In this research, an impedimetric immunosensor was first developed for the rapid detection of E. coli O157:H7 and S. Typhimurium in foods. It was based on the techniques of immunomagnetic separation, enzyme labelling, and electrochemical impedance spectroscopy …

Photoluminescence Measurement On Low-Temperature Metal Modulation Epitaxy Grown Gan, Yang Wu

Graduate Theses and Dissertations

A low-temperature photoluminescence (PL) study was conducted on low-temperature metal modulation epitaxy (MME) grown GaN. By comparing the PL signal from high temperature grown GaN buffer layers, and MME grown cap layers on top of the buffer layers, it was found that MME grown GaN cap has a significantly greater defect-related emission. The band edge PL from MME grown GaN found to be 3.51eV at low temperature. The binding energy of the exciton in GaN is determined to be 21meV through temperature dependence analysis. A PL peak at 3.29eV was found in the luminescence of the MME grown cap layer, …

Study Of Plasmonic Properties Of The Gold Nanorods In The Visible To Near Infrared Light Regime, Pijush Kanti Ghosh

Graduate Theses and Dissertations

Nanostructures of noble metals show unique plasmonic behavior in the visible to near-infrared light range. Gold nanostructures exhibit a particularly strong plasmonic response for these wavelengths of light. In this study we have investigated optical enhancement and absorption of gold nanorods with different thickness using finite element method simulations. This study reports on the resonance wavelength of the sharp-corner and round-corner rectangles of constant length 100 nm and width 60 nm. The result shows that resonance wavelength depends on the polarization of the incident light; there also exists a strong dependence of the optical enhancement and absorption on the thickness …

Acceleration Of Ddscat Computation By Parallelization On A Supercomputer, Manoj V. Seeram

Chemical Engineering Undergraduate Honors Theses

The DDSCAT software is enabled for use of MPI or OpenMP to distribute calculation of different particle orientations amongst multiple processors on a high performance system. Run times for these simulations have been tested to take hours or days however and simulating varying orientations is not always necessary. If a simulation with only one particle orientation is submitted, DDSCAT could still potentially parallelize the simulation by wavelength calculations but it is unknown if this is the case. In this paper, we will be (i) quantifying the reduction in computation time that MPI provides relative to an equivalent MPI disabled simulation …

Optical Analysis And Fabrication Of Micro And Nanoscale Plasmonically Enhanced Devices, Avery M. Hill

Physics Undergraduate Honors Theses

Plasmonic nanostructures have been shown to act as optical antennas that enhance optical devices due to their ability to focus light below the diffraction limit of light and enhance the intensity of the incident light. This study focuses on computational electromagnetic (CEM) analysis of two devices: 1) GaAs photodetectors with Au interdigital electrodes and 2) Au thin-film microstructures. Experiments showed that the photoresponse of the interdigital photodetectors depend greatly on the electrode gap and the polarization of the incident light. Smaller electrode gap and transverse polarization give rise to a larger photoresponse. It was also shown that the response from …

Phase-Field Models For Simulating Physical Vapor Deposition And Microstructure Evolution Of Thin Films, James Stewart Jr.

Graduate Theses and Dissertations

The focus of this research is to develop, implement, and utilize phase-field models to study microstructure evolution in thin films during physical vapor deposition (PVD). There are four main goals to this dissertation. First, a phase-field model is developed to simulate PVD of a single-phase polycrystalline material by coupling previous modeling efforts on deposition of single-phase materials and grain evolution in polycrystalline materials. Second, a phase-field model is developed to simulate PVD of a polymorphic material by coupling previous modeling efforts on PVD of a single-phase material, evolution in multiphase materials, and phase nucleation. Third, a novel free energy functional …

Nanoscale Frictional Properties Of Nickel With One-Dimensional And Two-Dimensional Materials, Timothy K. Schlenger

Mechanical Engineering Undergraduate Honors Theses

When looking at the nanoscale, material interface interactions have been observed to exhibit particularly interesting properties. Our research looks into various combinations of carbyne and graphene atop a nickel block to look into the interface friction properties between them. Both the carbyne and graphene are tested using steered molecular dynamics (SMD) in sheering and peeling directions along the surface of the nickel block. These tests are then analyzed by comparing the magnitude of the acting force versus the displacement of the carbon allotrope sample across the nickel block. It is found that as the width of a carbon allotrope sample …

Non-Directional Conjugation Of Fluorescent Antibodies To Gold Nanoparticles For Stem Cell Therapy, Kunal B. Shah

Biomedical Engineering Undergraduate Honors Theses

The objective of this study was to design citrate-coated gold nanoparticles conjugated with FITC-IgG, a fluorescent antibody, and to qualitatively and quantitatively measure the resulting fluorescent emission. Optical properties of the gold nanoparticles were measured at various stages to provide evidence of successful conjugation. The absorbance spectrum of the citrate gold nanoparticles was compared to that of the reaction mixture containing the gold nanoparticles and the FITC-IgG. A noticeable broadening of the absorption peak was observed at 519 nm indicating a surface modification of the gold nanoparticles. Fluorescence data was obtained with a fluorospectrometer and revealed a significant amount of …

Optical Analysis And Fabrication Of Micro And Nanoscale Plasmonically Enhanced Devices, Avery M. Hill

Mechanical Engineering Undergraduate Honors Theses

Plasmonic nanostructures have been shown to act as optical antennas that enhance optical devices due to their ability to focus light below the diffraction limit of light and enhance the intensity of the incident light. This study focuses on computational electromagnetic (CEM) analysis of two devices: 1) GaAs photodetectors with Au interdigital electrodes and 2) Au thin-film microstructures. Experiments showed that the photoresponse of the interdigital photodetectors depend greatly on the electrode gap and the polarization of the incident light. Smaller electrode gap and transverse polarization give rise to a larger photoresponse. It was also shown that the response from …

Atomic Force Microscopy Based Dna Analysis, Drew Creighton

Mechanical Engineering Undergraduate Honors Theses

This report explores dry and wet scanning of a surface and DNA pickup using an AFM, as well as fluorescent staining of DNA. Dry and wet scans of DNA were obtained using a cantilever AFM tip in tapping mode. Dry scans were found to be clearer than wet scans; however, the drying process was found to decrease the thickness of DNA 2–4 times less than its original thickness. Alternately, wet scans were found to be less clear than dry scans and introduced more noise into the images obtained. Additionally, DNA kept its initial thickness during wet scanning. DNA was capable …