Nanoscience and Nanotechnology Commons^™

Tetradymite Topological Insulators : Towards High Performance Broadband Photodetection, Asish Parbatani

Legacy Theses & Dissertations (2009 - 2024)

Topological insulators are characterized by the presence of a finite energy gap in the bulk state and a conducting metallic surface state consisting of odd number of Dirac cones. The conducting surface states are along the edge boundaries, free from disorders and are protected by time reversal symmetry. The presence of Dirac cone leads to universal optical absorption phenomenon like graphene. This phenomenon of universal optical absorption leads to frequency independent photoexcitation of carriers. Bi2Te3, Sb2Te3 and Bi2Se3 belong to tetradymite topological insulators (TTI) family and are often referred to as 3D layered materials. Theoretical predictions characterize TTIs by low …

Cvd Molybdenum Disulfide : Material And Device Engineering, Eui Sang Song

Legacy Theses & Dissertations (2009 - 2024)

Molybdenum disulfide (MoS2) is a semiconducting 2D layered material that has attracted a lot of attention due to its material properties for electronics and optoelectronics device applications. These include a layer-dependent band gap, an indirect to direct energy transition at monolayer state, and strong light-matter interaction. A large majority of 2D materials and devices have been studied through micromechanical exfoliation for extraction and electron beam lithography for device fabrication. These methodologies while able to generate high quality materials and precisely fabricated devices, are not suitable for large scale production. Efforts have been made to make MoS2 and other 2D materials …

Magnetotransport In Zrte5 Crystals, Maksim Andreevich Sultanov

Graduate Research Theses & Dissertations

ZrTe5 is a topological material that is predicted to have a strain or temperature induced phase transition from a topological insulator state into a Weyl/Dirac semimetal state. In this study I find that there is insufficient evidence to support the claims for the existence of such a phase transition. I performed magnetoresistivity measurements using a Quantum Design Physical Properties Measurement System (PPMS) to measure the transverse and longitudinal resistivities at various temperatures and different strengths and orientations of the magnetic field. The measurement results were analyzed using OriginPro to determine the carrier mobility and density and to determine the temperature …

Studies On Semiconductor Gas Sensors Using Nanostructure Growth Employing Ortho-Glancing Angle Deposition, Dean R. Walters

Graduate Research Theses & Dissertations

A program of research was undertaken to develop the next generation of metal oxide gas sensors, which, for the purpose of this research, were made from materials using a unique approach of glancing angle deposition (GLAD) that is scalable to large scale production. This research seeks to demonstrate that high-sensitivity sensors can be produced. The sensors were examined in a test system of novel design in which the units underwent performance measurements using analyte gases, such as carbon dioxide, nitrogen, and water.

Gas sensors can be improved by increasing the surface area of the active sensing media, and in this …

Straintronic Nanomagnetic Devices For Non-Boolean Computing, Md Ahsanul Abeed

Theses and Dissertations

Nanomagnetic devices have been projected as an alternative to transistor-based switching devices due to their non-volatility and potentially superior energy-efficiency. The energy efficiency is enhanced by the use of straintronics which involves the application of a voltage to a piezoelectric layer to generate a strain which is ultimately transferred to an elastically coupled magnetostrictive nanomaget, causing magnetization rotation. The low energy dissipation and non-volatility characteristics make straintronic nanomagnets very attractive for both Boolean and non-Boolean computing applications. There was relatively little research on straintronic switching in devices built with real nanomagnets that invariably have defects and imperfections, or their adaptation …

Engineering Magnetic Properties Of Nanoparticles For Biomedical Applications And Magnetic Thin Film Composite Heterostructures For Device Applications., Shivakumar Hunagund

Theses and Dissertations

The motivation of this study is to investigate the size dependent properties of Gadolinium silicide nanoparticles and their potential applications in Biomedicine. We use two approaches in our investigation - size dependence and possible exchange interaction in a core-shell structure. Past results showed Gd₅Si₄ NPs exhibit significantly reduced echo time compared to superparamagnetic iron oxide nanoparticles (SPION) when measured in a 7 T magnetic resonance imaging (MRI) system. This indicates potential use of Gd₅Si₄ ferromagnetic nanoparticles as T2 contrast agents for MRI.

Until recently most contrast agents (CA) that are used in Magnetic Resonance …

The Fabrication And Characterization Of Metal Oxide Nanoparticles Employed In Environmental Toxicity And Polymeric Nanocomposite Applications, Matthew Logan Hancock

Theses and Dissertations--Chemical and Materials Engineering

Ceria (cerium oxide) nanomaterials, or nanoceria, have commercial catalysis and energy storage applications. The cerium atoms on the surface of nanoceria can store or release oxygen, cycling between Ce³⁺ and Ce⁴⁺, and can therefore act as a therapeutic to relieve oxidative stress within living systems. Nanoceria dissolution is present in acidic environments in vivo. In order to accurately define the fate of nanoceria in vivo, nanoceria dissolution or stabilization is observed in vitro using acidic aqueous environments.

Nanoceria stabilization is a known problem even during its synthesis; in fact, a carboxylic acid, citric acid, is …

Development And Demonstration Of A Processing And Assembly Pathway For A 3d-Synchronous Field Programmable Gate Array, Robert Carroll

Legacy Theses & Dissertations (2009 - 2024)

Field Programmable Gate Arrays (FPGA) are integrated circuits which can implement virtually any digital function and can be configured by a designer after manufacturing. This is beneficial when dedicated application specific runs are not time or cost effective; however, this flexibility comes at the cost of a substantially higher interconnect overhead. Three-dimensional (3D) integration can offer significant improvements in the FPGA architecture by stacking multiple device layers and interconnecting them in the third or vertical dimension, through the substrate, where path lengths are greatly reduced. This will allow for a higher density of devices and improvements in power consumption, signal …

Mechanistic Investigation Of Antimony Carboxylate Photoresists For Euv Lithography, Michael Murphy

Legacy Theses & Dissertations (2009 - 2024)

In 2019, Extreme Ultraviolet (EUV) lithography begins its integration into high volume manufacturing to replace 193-nm lithography at key steps in the fabrication of integrated circuits. To achieve the requirements of the 7- and 5-nm nodes, a new photoresist technology is required to replace traditional chemically-amplified photoresists (CAR). One novel technology incorporates metal atoms with high EUV absorptivity into the photoresist. In this work, we describe the development, evaluation and mechanistic investigation of triorganoantimony(V) dicarboxylate complexes as novel photoresists for EUV lithography.

Engineering Plasmonic Nanostructures For Light Management And Sensing, Sujan Phani Kumar Kasani

Graduate Theses, Dissertations, and Problem Reports

The two major global problems are to provide health safety and to meet energy demands for ever growing population on a large scale. The study of light interaction with nanostructures has shown a promising solution in improving the fields of bio-sensor and solar energy devices which addresses above mentioned two major global problems. Nanostructures have tunable physicochemical properties such as light absorption, electrical and thermal properties unlike bulk materials, which gives an advantage in applications like bio-sensing and energy harvesting devices. The development of nanofabrication techniques along with the discovery of Surface Enhanced Raman Scattering (SERS) and Plasmon Enhanced Fluorescence …