Nanoscience and Nanotechnology Commons^™

Optical Properties Of Nanostructured Dielectric Coatings, Brandon Giatti

Dissertations and Theses

Solar cells have extrinsic losses from a variety of sources which can be minimized by optimization of the design and fabrication processes. Reflection from the front surface is one such loss mechanism and has been managed in the past with the usage of planar antireflection coatings. While effective, these coatings are each limited to a single wavelength of light and do not account for varying incident angles of the incoming light source. Three-dimensional nanostructures have shown the ability to inhibit reflection for differing wavelengths and angles of incidence. Nanocones were modeled and show a broadband, multi-angled reflectance decrease due to …

Transport Properties Of Nano-Silica Contained Self-Consolidating Concrete, Borhan Moradi

UNLV Theses, Dissertations, Professional Papers, and Capstones

In this research study, transport properties of various self-consolidating concretes (SCCs) containing nano-particles (SiO2) were investigated. Nano-silica replaced a portion of the cementitious materials at different replacement levels ranging from 1.5 to 7.5% by weight. For the purpose of this investigation, flow, bulk, and transport properties of SCCs were studied. The investigated transport properties were absorption, water penetration, rapid chloride permeability, capillary absorption, rapid migration, and chloride diffusion. Transport properties of nano-silica SCCs were also compared to those of equivalent silica fume (micro silica) contained concretes, as well as those of control mixture (concrete without nano or micro silica).

Test …

Investigating Quantum Oscillations In The Thermal Coefficient Of Resistivity Of Ultra-Thin Ag Capping Layers On Cu For Ic Interconnect Applications, Elroy Tatem

Legacy Theses & Dissertations (2009 - 2024)

As the semiconductor industry continues to scale feature sizes, scattering from phonons, surfaces, and grain boundaries result in an increase of metal interconnect resistivity in state-of-the-art integrated circuits (ICs). The interconnect chapter of the 2011 International Technology Roadmap for Semiconductors (ITRS) stated that there are currently no manufacturable solutions in the near term for suitable Cu replacements. Previous studies of thin Ag films deposited on Cu demonstrated oscillations in the electron-phonon interactions within the bilayer system. This thesis investigates oscillations in the resistive properties of the Ag/Cu bilayer system and discusses the applicability of these oscillations to the resistivity challenges …

Nanostructured Tiox As A Catalyst Support Material For Proton Exchange Membrane Fuel Cells, Richard Phillips

Legacy Theses & Dissertations (2009 - 2024)

Recent interest in the development of new catalyst support materials for proton exchange membrane fuel cells (PEMFCs) has stimulated research into the viability of TiO₂-based support structures. Specifically, substoichiometric TiO₂ (TiO_x) has been reported to exhibit a combination of high conductivity, stability, and corrosion resistance. These properties make TiO_x-based support materials a promising prospect when considering the inferior corrosion resistance of traditional carbon-based supports. This document presents an investigation into the formation of conductive and stable TiO_x thin films employing atomic layer deposition (ALD) and a post deposition oxygen reducing anneal (PDORA). …

Exposure Assessment And Risk Management Of Engineered Nanoparticles : Investigation In Semiconductor Wafer Processing, Michele Shepard

Legacy Theses & Dissertations (2009 - 2024)

Engineered nanomaterials (ENMs) are currently used in hundreds of commercial products and industrial processes, with more applications being investigated. Nanomaterials have unique properties that differ from bulk materials. While these properties may enable technological advancements, the potential risks of ENMs to people and the environment are not yet fully understood. Certain low solubility nanoparticles are more toxic than their bulk material, such that existing occupational exposure limits may not be sufficiently protective for workers. Risk assessments are currently challenging due to gaps in data on the numerous emerging materials and applications as well as method uncertainties and limitations.

Fundamental Studies Of Supported Graphene Interfaces : Defect Density Of States In Graphene Field Effect Transistors (Fets) And Ideal Graphene - Silicon Schottky Diodes, Dhiraj Sinha

Legacy Theses & Dissertations (2009 - 2024)

The physics of transport in atomically thin 2D materials is an active area of research, important for understanding fundamental properties of reduced dimensional materials and for applications. New phenomena based on graphene may include properties of topologically protected insulators. Applications of these materials are envisioned in electronics, optoelectronics and spintronics.

Growth And Characterization Of Graphene On Cuni Substrates, Parul Tyagi

Legacy Theses & Dissertations (2009 - 2024)

Graphene is a single layer of sp2 bonded carbon atoms that crystallizes in the honeycomb structure. Because of its true two-dimensional structure, it has very unique electrical properties, including a very high carrier mobility that is symmetric for holes and electrons. To realize these unique properties, it is important to develop a method for growing graphene films with uniform thickness and low defect density. One of the most popular methods of growth is by chemical vapor deposition on Cu substrates, because it is self-limited. However many applications require the growth of graphene films that are more than one atomic layer …

Radiation Effects In Gate-All-Around Silicon Nanowire Mosfets And Carbon Nanotube P-N Diodes, Everett Steven Comfort

Legacy Theses & Dissertations (2009 - 2024)

The scaling of MOSFETs has resulted in short channel effects that increase their power consumption above acceptable levels. In order to lower the power dissipation, new device designs and materials are being considered. For example, multiple-gate MOSFETs, including the gate-all-around silicon nanowire (GAA SiNW) MOSFET, are known to reduce short channel effects. Furthermore, new high-mobility channel materials such as single-walled carbon nanotubes (SWNTs) can be integrated to allow for further scaling of the supply voltage, again aiding in lowering power dissipation.

Biomacromolecule Conjugated Nanofiber Scaffold For Salivary Gland Tissue Engineering, Kavitha Jayarathanam

Legacy Theses & Dissertations (2009 - 2024)

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First-Principles Study Of The Electric Field Effect On The Water-Adsorbed Rutile Titanium Dioxide Surface, Abraham L. Hmiel

Legacy Theses & Dissertations (2009 - 2024)

TiO₂ is a semiconducting material that has been used extensively in many industrial applications, and recently has become a candidate for photocatalytic water splitting, fuel cell anode support materials, sensors, and other novel nanodevices. The interface of TiO2 with water, historically well-studied but still poorly understood, presents a ubiquitous environmental challenge towards the ultimate practical usefulness of these technologies. Ground-state density functional theory (DFT) calculations studying the characteristics of molecular adsorption on model surfaces have been studied for decades, showing constant improvement in the description of the energetics and electronic structure at interfaces. These simulations are invaluable in the …

Metrology Of Epitaxial Thin Films And Periodic Nanostructures Using High Resolution X-Ray Diffraction Techniques, Manasa Medikonda

Legacy Theses & Dissertations (2009 - 2024)

The continued scaling of device size to achieve higher performance and/or lower power operation at lower cost is driving research and development into new, 3D transistor structures such as the FinFET. This research and development effort is highlighting the need for new, advanced measurement capability that is highly accurate, reliable, rapid, and nondestructive. Periodic arrays of fin structures enable process monitoring at each level of fabrication and the maintenance of overall device yield. High resolution x-ray diffraction (HR XRD) has been shown to provide unique capability of characterizing blanket thin films and structural parameters of periodic arrays of fins fabricated …