Materials Science and Engineering Commons^™

The Effect Of Energy Deposition On Pattern Resolution In Electron Beam Lithography, Ananthan Raghunathan

Legacy Theses & Dissertations (2009 - 2024)

Electron beam lithography is one of the most important tools for nanofabrication. Electron beam lithography has consistently been able to offer higher resolution, typically better than 10 nm or so, compared to other techniques. In this work the contribution of electron-substrate interaction to pattern resolution is investigated.

Plasma-Enhanced Atomic Layer Deposition Of Ruthenium-Titanium Nitride Mixed-Phase Layers For Direct-Plate Liner And Copper Diffusion Barrier Applications, Adam James Gildea

Legacy Theses & Dissertations (2009 - 2024)

Current interconnect networks in semiconductor processing utilize a sputtered TaN diffusion barrier, Ta liner, and Cu seed to improve the adhesion, microstructure, and electromigration resistance of electrochemically deposited copper that fills interconnect wires and vias. However, as wire/via widths shrink due to device scaling, it becomes increasingly difficult to have the volume of a wire/via be occupied with ECD Cu which increases line resistance and increases the delay in signal propagation in IC chips. A single layer that could serve the purpose of a Cu diffusion barrier and ECD Cu adhesion promoter could allow ECD Cu to occupy a larger …

Ruco To Extend The Scalability Of Ultra-Thin Direct Plate Liners, Daniel Verne Greenslit

Legacy Theses & Dissertations (2009 - 2024)

In traditional semiconductor technology a sputtered copper seed layer is used to improve the adhesion, microstucture, and electromigration characteristics of electrochemically deposited (ECD) copper. The seed layer is deposited on top of a Ta/TaN stack. The Ta layer acts as an adhesion and nucleation layer for the copper seed and the TaN serves as a diffusion barrier for the Cu. As the line widths continue to shrink, scaling each of these layers becomes more difficult. It would be advantageous for the interconnect to be composed of as much copper as possible, transitioning from the traditional liner seed stack to a …

Fabrication Of Two-Dimensional Nanostructures On Glass Using Nanosphere Lithography, Elmer Jim Wang

Wayne State University Theses

It is desired to have artificial optical materials with controllable optical properties. Optical glass is the most common optical material for various applications. This research will attempt to create a thin layer on the substrate with controllable optical properties. The thin layer is a composite material with nanoscale features and controllable refractive index. Two-dimensional (2D) nanostructures will be created on the surface of optical glass using nanosphere lithography. In comparison with conventional techniques, this approach is more efficient and cost-effective for the creation of large areas of thin surface layers as an artificial material. A uniform monolayer of nanospheres will …

Infrared Optical Properties Of Amorphous And Nanocrystalline Ta2o5 Thin Films, Trevor J. Bright, J. I. Watjen, Zhuomin Zhang, Christopher Muratore, Andrey A. Voevodin, D. I. Koukis, David B. Tanner, Daniel J. Arenas

Chemical and Materials Engineering Faculty Publications

The optical constants of tantalum pentoxide (Ta 2O5) are determined in a broad spectral region from the visible to the far infrared. Ta 2O5 films of various thicknesses from approximately 170 to 1600 nm aredeposited using reactive magnetron sputtering on Si substrates. X-ray diffraction shows that the as-deposited films are amorphous, and annealing in air at 800 °C results in the formation of nanocrystallineTa 2O5. Ellipsometry is used to obtain the dispersion in the visible and near-infrared. Two Fourier-transform infrared spectrometers are used to measure the transmittance and reflectance at wavelengths from 1 to 1000 μm. The surface topography and …

The Use Of Elemental Powder Mixes In Laser-Based Additive Manufacturing, Rodney Michael Clayton

Masters Theses

"This study examines the use and functionality of laser depositing alloys from mixes of elemental metallic powders. Through the use of laser-based additive manufacturing (LAM), near net-shaped 3-Dimensional metallic parts can be produced in a layer-by-layer fashion. It is customary for pre-alloyed powders to be used in this process. However, mixes of elemental powders can be used to produce alloys that are formed during the deposition process. This alternative technique requires that the elemental powders adequately mix during deposition for a homogeneous deposit to be produced. Cost savings and versatility are among several of the advantages to using elemental powder …

Effects Of Material Variables And Process Parameters On Properties Of Investment Casting Shells, Priyatham Tumurugoti

Masters Theses

"Manufacture of investment casting shells is a complex process. The choice of raw materials - refractory powders or grains, binders and additives - affects the properties of investment casting shells. In this study, different systems of shells were prepared, according to a design of experiments, with commercially available raw materials that differ in chemistry, particle size or particle size distribution. Shell strength was measured in green, fired and cooled, and hot conditions and the results were analyzed for strength-material property relation. Various microstructures of polished cross sections of these shells were characterized using scanning electron microscope. It was determined that …

Copper Indium Diselenide Nanowire Arrays In Alumina Membranes Deposited On Molybdenum And Other Back Contact Substrates, Bhavananda R. Nadimpally

Theses and Dissertations--Electrical and Computer Engineering

Heterojunctions of CuInSe₂ (CIS) nanowires with cadmium sulfide (CdS) were fabricated demonstrating for the first time, vertically aligned nanowires of CIS in the conventional Mo/CIS/CdS stack. These devices were studied for their material and electrical characteristics to provide a better understanding of the transport phenomena governing the operation of heterojunctions involving CIS nanowires. Removal of several key bottlenecks was crucial in achieving this. For example, it was found that to fabricate alumina membranes on molybdenum substrates, a thin interlayer of tungsten had to be inserted. A qualitative model was proposed to explain the difficulty in fabricating anodized aluminum oxide …

Novel Nanostructures And Processes For Enhanced Catalysis Of Composite Solid Propellants, Robert Draper

Electronic Theses and Dissertations

The purpose of this study is to examine the burning behaviour of composite solid propellants (CSP) in the presence of nanoscale, heterogenous catalysts. The study targets the decomposition of ammonium perchlorate (AP) as a key component in the burning profile of these propellants, and seeks to identify parameters of AP decomposition reaction that can be affected by catalytic additives. The decomposition behavior of AP was studied in the presence of titanium dioxide nanoparticles in varying configurations, surface conditions, dopants, morphology, and synthesis parameters with the AP crystals. The catalytic nanoparticles were found to enhance the decomposition rate of the ammonium …

Scandia And Ceria Stabilized Zirconia Based Electrolytes And Anodes For Intermediate Temperature Solid Oxide Fuel Cells: Manufacturing And Properties, Yan Chen

Electronic Theses and Dissertations

Mesoscale optical phenomena occur when light interacts with a number of different types of materials, such as biological and chemical systems and fabricated nanostructures. As a framework, mesoscale optics unifies the interpretations of the interaction of light with complex media when the outcome depends significantly upon the scale of the interaction. Most importantly, it guides the process of designing an optical sensing technique by focusing on the nature and amount of information that can be extracted from a measurement. Different aspects of mesoscale optics are addressed in this dissertation which led to the solution of a number of problems in …

Design, Fatigue, And Strength Analysis Of A Tie Rod Hydraulic Cylinder Bolt, Jacob Roemen, Donald Webber

The Journal of Undergraduate Research

This report illustrates strength and fatigue analysis completed on a tie rod hydraulic cylinder bolt from a Lion TX 2500 tie rod hydraulic cylinder. The goal was to: solve for total clamping force, damping force per bolt at 90% proof load strength, amount of force per bolt, find the required number of bolts to hold the hydraulic cylinder together, solve for bolt spacing requirements, estimate a safety factor based on proof load strength, nut shear strength, required nut thickness, the least number of threads that must be engaged, estimate R.R. Moore Bending Fatigue Strengths, estimate the maximum value of P …

A Three-Dimensional Quantitative Understanding Of Short Fatigue Crack Growth In High Strength Aluminum Alloys, Wei Wen

Theses and Dissertations--Chemical and Materials Engineering

The behaviors of short fatigue crack (SFC) propagation through grain boundaries (GBs) were monitored during high cycle fatigue in an Al-Li alloy AA8090. The growth behaviors of SFCs were found to be mainly controlled by the twist components (α) of crack plane deflection across each of up to first 20 GBs along the crack path. The crack plane twist at the GB can result in a resistance against SFC growth; therefore SFC propagation preferred to follow a path with minimum α at each GB. In addition to the grain orientation, the tilting of GB could also affect α.

An experiment …

Numerical Modeling And Characterization Of Vertically Aligned Carbon Nanotube Arrays, Johnson Joseph

Theses and Dissertations--Mechanical and Aerospace Engineering

Since their discoveries, carbon nanotubes have been widely studied, but mostly in the forms of 1D individual carbon nanotube (CNT). From practical application point of view, it is highly desirable to produce carbon nanotubes in large scales. This has resulted in a new class of carbon nanotube material, called the vertically aligned carbon nanotube arrays (VA-CNTs). To date, our ability to design and model this complex material is still limited. The classical molecular mechanics methods used to model individual CNTs are not applicable to the modeling of VA-CNT structures due to the significant computational efforts required. This research is to …

The Study Of Photo-Reduction Of Cerium Oxide Nanoparticles In Presence Of Dextran: An Attempt In Understanding The Functionality Of The System, Swetha Barkam

Electronic Theses and Dissertations

Malignant melanoma cancer is the sixth common cancer diagnosed in the United States. Surgery, chemotherapy and radiation are some of the successful techniques in killing tumor cells. However, in these techniques, it is not easy to distinguish tumor cells from the healthy once which inadvertently get exposed to chemical agent/radiation. Therefore it is required to develop an anticancer agent which selectively kills the cancer cells, while still protecting the normal tissues. In our preliminary work, we have shown that Dextran (1000Da) coated Cerium oxide nanoparticles (Dex-CNPs) selectively kills the cancer cells (50% killing at a concentration of 150μM) without inducing …

Tailoring The Properties Of Polyelectrolyte Coated Cerium Oxide Nanoparticles As A Function Of Molecular Weight, Shashank Saraf

Electronic Theses and Dissertations

The application of Cerium oxide nanoparticles (CNPs) for therapeutic purposes requires a stable dispersion of nanoparticles in biological environment. The objective of this study is to tailor the properties of polyelectrolyte coated CNPs as a function of molecular weight to achieve a stable and catalytic active dispersion. This was achieved by coating CNPs with polyacrylic acid (PAA) which increased the dispersion stability of CNPs and enhanced the catalytic ability. The stability of PAA coating was analysed using the change in the Gibbs free energy computed by Langmuir adsorption model. The adsorption isotherms were determined using soft particle electrokinetics which overcomes …

First Principle Studies Of Cu-Carbon Nanotube Hybrid Structures With Emphasis On The Electronic Structures And The Transport Properties, Chengyu Yang

Electronic Theses and Dissertations

Carbon nanotubes have been regarded as ideal building blocks for nanoelectronics and multifunctional nanocomposites due to their exceptional strength, stiffness, flexibility, as well as their excellent electrical properties. However, carbon nanotube itself has limitations to fulfill the practical application needs: 1) an individual carbon nanotube has a low density of states at the Fermi level, and thus its conductivity is only comparable to moderate metals but lower than that of copper. 2) Metallic and semiconducting nanotubes are inherently mixed together from the synthesis, and the selection/separation is very difficult with very low efficiency. 3) Carbon nanotubes alone cannot be used …

Interdiffusion Reaction Between Uranium-Zirconium And Iron, Young Joo Park

Electronic Theses and Dissertations

U-Zr metallic fuels cladded in Fe-alloys are being considered for application in an advanced Sodium-Cooled Fast Reactor (SFR) that can recycle the U-Zr fuels and minimize the long-lived actinide waste. To understand the complex fuel-cladding chemical interaction of the U-Zr metallic fuel with Fe-alloys, a systematic multicomponent diffusion study was carried out using solid-to-solid diffusion couples. The U-10 wt.% Zr vs. pure Fe diffusion couples were assembled and annealed at temperatures, 630, 650 and 680°C for 96 hours. Development of microstructure, phase constituents, and compositions developed during the thermal anneals were examined by scanning electron microscopy, transmission electron microscopy and …

High Volume Fraction Mg-Based Nanocomposites: Processing, Microstructure And Mechanical Behavior, Jinling Liu

Electronic Theses and Dissertations

Mg-based metal matrix nanocomposites (MMNCs) with mechanical properties, superior to those of coarse-grained composites, are promising structural materials for applications in the automotive and aerospace industries. The research in this area was primarily focused earlier on either micro-scaled reinforcements or nano-scaled reinforcements with very low volume fractions. MMNCs with high volume fractions have not been explored yet. In this research, we study the processing, microstructures and properties of MMNCs containing ceramic nanoparticles up to 30 vol.%. We first investigated the mechanical alloying of Al2O3 nanoparticles and pure Mg under high-energy ball milling conditions. The phase evolution and their distribution were …

Corrosion Behaviour Of Aisi 304 Stainless Steel In Contact With Eutectic Salt For Concentrated Solar Power Plant Applications, Omar Ahmed

Electronic Theses and Dissertations

In response to the extensive energy demands on national and global levels, concentrated solar power (CSP) plants are designed to harness and convert solar energy to electricity. For such green energy application, robust, reliable and durable materials for CSP constructions are required. The corrosion resistance is among many parameters to consider in these thermalelectrical stations such as for pipes and storage tanks in CSP. In this investigation, the corrosion behavior of AISI 304 stainless steel (18 wt. % Cr, 8 wt. % Ni) with the heat transfer fluid, also known as solar salt, has been examined. The ternary eutectic salt …

Interdiffusion And Impurity Diffusion In Magnesium Solid Solutions, Catherine Kammerer

Electronic Theses and Dissertations

Magnesium, being lightweight, offers potential to be developed into extensive structural applications. The transportation segment has particular interest in Mg and Mg alloy for applications where reduced vehicle weight is proportional to increased fuel efficiency. Aluminum and zinc are two of the most common alloying elements in commercial Mg alloys. They improve the physical properties of Mg through solid solution strengthening and precipitation hardening. Diffusion plays a key role in the kinetics of and microstructural development during solidification and heat treatment. However, there is limited diffusion data available for Mg and Mg alloys. In particular, because Al is monoisotopic, tracer …