Nanoscience and Nanotechnology Commons^™

Method For Increasing The Efficiency Of Organic Photovoltaic Cells, Jinsong Huang, Yongbo Yuan

Department of Mechanical and Materials Engineering: Faculty Publications

The present invention is directed to an organic photovoltaic cell that contains one or more dipole regions generally disposed between an organic active region and the electrodes and a process for producing such an organic photovoltaic cell.

Cell Permeabilization And Inhibition Of Voltage-Gated Ca²+ And Na+ Channel Currents By Nanosecond Pulsed Electric Fields, Vasyl Nesin, Angela M. Bowman, Shu Xiao, Andrei G. Pakhomov

Bioelectrics Publications

Previous studies have found that nanosecond pulsed electric field (nsPEF) exposure causes long-term permeabilization of the cell plasma membrane. In this study, we utilized the whole-cell patch-clamp method to study the nsPEF effect on currents of voltage-gated (VG) Ca²⁺ and Na⁺ channels (I_Ca and I_Na) in cultured GH3 and NG108 cells. We found that a single 300 or 600 ns pulse at or above 1.5-2 kV/cm caused prolonged inhibition of I_Ca and I_Na. Concurrently, nsPEF increased a non-inactivating leak current (I_leak), presumably due to the formation of nanoelectropores or larger …

Gaining Insight Into The Physics Of Dynamic Atomic Force Microscopy In Complex Environments Using The Veda Simulator, Daniel Kiracofe, John Melcher, Arvind Raman

Birck and NCN Publications

Dynamic atomic force microscopy (dAFM) continues to grow in popularity among scientists in many different fields, and research on new methods and operating modes continues to expand the resolution, capabilities, and types of samples that can be studied. But many promising increases in capability are accompanied by increases in complexity. Indeed, interpreting modern dAFM data can be challenging, especially on complicated material systems, or in liquid environments where the behavior is often contrary to what is known in air or vacuum environments. Mathematical simulations have proven to be an effective tool in providing physical insight into these non-intuitive systems. In …

Full Band Atomistic Modeling Of Homo-Junction Ingaas Band-To-Band Tunneling Diodes Including Band Gap Narrowing, Woo-Suhl Cho, Mathieu Luisier, Dheeraj Mohata, Suman Datta, David Pawlik, Sean L. Rommel, Gerhard Klimeck

Birck and NCN Publications

A homo-junction In0.53Ga0.47As tunneling diode is investigated using full-band, atomistic quantum transport approach based on a tight-binding model (TB) and the Non-equilibrium Green’s Function formalism. Band gap narrowing (BGN) is included in TB by altering its parameters using the Jain-Roulston model. BGN is found to be critical in the determination of the current peak and the second turn-on in the forward bias region. An empirical excess current that mimics additional recombination paths must be added to the calculation to model the diode behavior in the valley current region. Overall the presented model reproduces experimental data well.

Feasibility, Accuracy, And Performance Of Contact Block Reduction Method For Multi-Band Simulations Of Ballistic Quantum Transport, Hoon Ryu, Hong-Hyun Park, Mincheol Shin, Dragica Vasileska, Gerhard Klimeck

Birck and NCN Publications

Numerical utilities of the contact block reduction (CBR) method in evaluating the retarded Green’s function are discussed for 3D multi-band open systems that are represented by the atomic tight-binding (TB) and continuum k * p (KP) band model. It is shown that the methodology to approximate solutions of open systems, which has been already reported for the single-band effective mass model, cannot be directly used for atomic TB systems, since the use of a set of zinc blende crystal grids makes the inter-coupling matrix non-invertible. We derive and test an alternative with which the CBR method can be still practical …

Macro And Microfluidic Flows For Skeletal Regenerative Medicine, Brandon D. Riehl, Jung Yul Lim

Department of Mechanical and Materials Engineering: Faculty Publications

Fluid flow has a great potential as a cell stimulatory tool for skeletal regenerative medicine, because fluid flow-induced bone cell mechanotransduction in vivo plays a critical role in maintaining healthy bone homeostasis. Applications of fluid flow for skeletal regenerative medicine are reviewed at macro and microscale. Macroflow in two dimensions (2D), in which flow velocity varies along the normal direction to the flow, has explored molecular mechanisms of bone forming cell mechanotransduction responsible for flow-regulated differentiation, mineralized matrix deposition, and stem cell osteogenesis. Though 2D flow set-ups are useful for mechanistic studies due to easiness in in situ and post-flow …

Polymeric Nanocarriers For The Regional And Systemic Delivery Of Therapeutics To And Through The Lungs, Balaji Bharatwaj

Wayne State University Dissertations

The lungs are considered as one of the fastest portals of entry to the bloodstream and oral inhalation (OI) has long been accepted as the preferred mode of administration of therapeutics to the respiratory tract. However, despite its advantages, the lungs have been largely underutilized to target ailments not only of systemic relevance but also several other grave conditions including lung cancer and tuberculosis. Polymeric nanocarriers (PNCs) have several advantages over other drug delivery vehicles including sustained release of moieties, ease of cellular internalization and improved targeting, and hence hold the promise to greatly augment the potential of OI therapies. …

Sacrificial Structure Preforms For Thin Part Machining, Scott Smith, Robert Wilhelm, Brian Dutterer, Harish Cherukuri, Gaurav Goel

Department of Mechanical and Materials Engineering: Faculty Publications

Thin parts are often difficult to create by machining because they have insufficient static and dynamic stiffness. Accurate thin parts are difficult to achieve due to clamping forces, cutting forces, residual stresses, and chatter. Sacrificial structure preforms support the part during machining, but they are not part of the finished component. Preforms may be created in many ways, including forging, welding, gluing, casting, or additive processes. They can be used in many workpiece materials including metals, polymers, and ceramics. We describe a novel process that uses sacrificial structures to make machining insensitive to the thinness of finished parts.

Modified Statistical Dynamical Diffraction Theory : A Novel Metrological Analysis Method For Partially Relaxed And Defective C Doped Si And Sige Heterostructures, Paul Kenneth Shreeman

Legacy Theses & Dissertations (2009 - 2024)

The statistical dynamical diffraction theory, which has been initially developed by late Kato remained in obscurity for many years due to intense and difficult mathematical treatment that proved to be quite challenging to implement and apply. With assistance of many authors in past (including Bushuev, Pavlov, Pungeov, and among the others), it became possible to implement this unique x-ray diffraction theory that combines the kinematical (ideally imperfect) and dynamical (the characteristically perfect diffraction) into a single system of equations controlled by two factors determined by long range order and correlation function within the structure. The first stage is completed by …

Generality In Nanotechnologies And Its Relationship To Economic Performance, Fernando Gomez Baquero

Legacy Theses & Dissertations (2009 - 2024)

In the history if economic analysis there is perhaps no more important question than the one of how economic development is achieved. For more than a century, economists have explored the role of technology in economic growth but there is still much to be learned about the effect that technologies, in particular emerging ones, have on economic growth and productivity. The objective of this research is to understand the relationship between nanotechnologies and economic growth and productivity, using the theory of General Purpose Technology (GPT)-driven economic growth. To do so, the Generality Index (calculated from patent data) was used to …

Development Of Iii-V P-Mosfets With High-Kappa Gate Stack For Future Cmos Applications, Padmaja Nagaiah

Legacy Theses & Dissertations (2009 - 2024)

As the semiconductor industry approaches the limits of traditional silicon CMOS scaling, non-silicon materials and new device architectures are gradually being introduced to improve Si integrated circuit performance and continue transistor scaling. Recently, the replacement of SiO2 with a high-k material (HfO2) as gate dielectric has essentially removed one of the biggest advantages of Si as channel material. As a result, alternate high mobility materials are being considered to replace Si in the channel to achieve higher drive currents and switching speeds. III-V materials in particular have become of great interest as channel materials, owing to their superior electron transport …

Al/Cuxo/Cu Memristive Devices : Fabrication, Characterization, And Modeling, Nathan Mcdonald

Legacy Theses & Dissertations (2009 - 2024)

Memristive devices have become very popular in recent years due to their potential to dramatically alter logic processing in CMOS circuitry. Memristive devices function as electrical potentiometers, allowing for such diverse applications as memory storage, multi-state logic, and reconfigurable logic gates.

Graphene-Based Post-Cmos Architecture, Sansiri Tanachutiwat

Legacy Theses & Dissertations (2009 - 2024)

The semiconductor industry relies on CMOS technology which is nearing its scaling limitations. In order to continue the historical growth rate of the device density of digital logic chips, novel nanomaterials and nanodevices will need to be developed.

Virus Capsids As Nanoscale Delivery Vessels Of Photoactive Compounds For Site-Specific Photodynamic Therapy, Brian Alexander Cohen

Legacy Theses & Dissertations (2009 - 2024)

The research presented in this work details the use of a viral capsid as an addressable delivery vessel of photoactive compounds for use in photodynamic therapy. Photodynamic therapy is a treatment that involves the interaction of light with a photosensitizing molecule to create singlet oxygen, a reactive oxygen species. Overproduction of singlet oxygen in cells can cause oxidative damage leading to cytotoxicity and eventually cell death. Challenges with the current generation of FDA-approved photosensitizers for photodynamic therapy primarily stem from their lack of tissue specificity. This work describes the packaging of photoactive cationic porphyrins inside the MS2 bacteriophage capsid, followed …

Micropatterned Electrospun Nanofibrous Substrates As Scaffolds For Engineered Salivary Glands, David Alexander Soscia

Legacy Theses & Dissertations (2009 - 2024)

The salivary gland is a complex organ exhibiting a branching, 3-dimensional structure made up of acinar (saliva-producing), and ductal (saliva transporting and modifying) epithelial cells. The high surface area of the gland allows it to efficiently provide the mouth with saliva, maintaining oral cleanliness and comfort. Salivary gland hypofunction, a significant clinical problem often caused by the autoimmune disease Sjögren's syndrome or head and neck radiation for cancer patients, affects millions of Americans and is characterized by a loss of function of salivary gland acinar cells. Chronic xerostomia, or dry mouth, arises as a result of salivary gland hypofunction and …

Measurement Of Electron Spin Transport In Graphene On 6h-Silicon Carbide(0001), Joseph Abel

Legacy Theses & Dissertations (2009 - 2024)

The focus of this thesis is to demonstrate the potential of wafer scale graphene spintronics. Graphene is a single atomic layer of sp2-bonded carbon atoms that has high carrier mobilities, making it a desirable material for future nanoscale electronic devices. The vision of spintronics is to utilize the spin of the electron to produce novel high-speed low power consuming devices. Materials with long spin relaxation times and spin diffusion lengths are needed to realize these goals. Graphene is an ideal material as it meets these requirements and is amenable to planar device geometries.

Evaluation Of Chemical Mechanical Planarization (Cmp) For The Removal Of Surface Defects In Extreme Ultraviolet Lithography (Euvl) Mask Substrates, Bradley Halligan Wood

Legacy Theses & Dissertations (2009 - 2024)

A modified CMP process was investigated and developed with the goal of removing surface defects (nanoscale depressions or `pits') from quartz mask blank substrates. Initially, quartz glass wafers were evaluated to observe surface roughness and defect introduction due to low down-force CMP processing. Following analysis of quartz glass wafers subjected to such processing it was determined that a CMP-based processing for pit removal of maskblank substrates was potentially viable. Consequently, a specially-designed mask carrier for investigating and developing CMP-based defect removal from EUV maskblank substrates was mounted on a Strasbaugh 6DS-SP CMP laboratory tool. A series of experiments was performed …

Development Of A Gas-Based Spectral Filter For Carbon Dioxide Laser Produced Plasma Extreme Ultraviolet Sources, Chimaobi Mbanaso

Legacy Theses & Dissertations (2009 - 2024)

Currently, extreme ultraviolet (EUV) lithography is a promising next generation lithography technique for enabling the scaling of device features beyond 22 nm. Out-of-band radiation in EUV exposure tools remains one of the critical issues that must be addressed before the implementation of this lithography technique for high volume manufacturing. Laser produced plasmas which use a carbon dioxide (CO₂) drive laser pulse are more likely to be used to generate EUV radiation because of their scalability to higher source power. The out-of-band spectrum at the intermediate focus of EUV sources that use a CO₂ laser produced plasma is …

Development Of An Industrial Fabrication Process For Next Generation, Thinner And Larger Crystalline Silicon (C-Si) Wafer-Based Solar Cells, Anh Viet Nguyen

Legacy Theses & Dissertations (2009 - 2024)

The world's solar cell production has grown rapidly and steadily with an annual average of 30% over the last two decades. Single and micro-crystalline silicon solar cells have been the major reason for this production increase. In 2009, silicon-based solar cells comprised almost 90% of worldwide photovoltaic module shipments.

Experimental And Theoretical Analysis Of Strain Engineered Aluminium Nitride On Silicon For High Quality Aluminium(X)Indium(Y)Gallium(1-X-Y)Nitride Epitaxy, Mihir Hemant Tungare

Legacy Theses & Dissertations (2009 - 2024)

III-Nitrides on Si are of great technological importance due to the availability of large area, epi ready Si substrates and the ability to heterointegrate with mature silicon micro and nanoelectronics. The major roadblock with realizing this is the large difference in thermal expansion coefficients and lattice constants between the two material systems. A novel technique developed in our research lab shows the potential of simultaneous and substantial reduction in dislocation and crack density in GaN on Si (111). Research undertaken in the current doctoral dissertation, validates the superior GaN quality on Si obtained using our technique and determines the factors …

(In, Al) Co-Doped Zinc Oxide As A Novel Material System For Quantum-Well Multilayer Thermoelectrics, Sean C. Teehan

Legacy Theses & Dissertations (2009 - 2024)

Waste heat recovery from low efficiency industrial processes requires high performance thermoelectric materials to meet challenging requirements. The efficiency such a device is quantified by the dimensionless figure of merit ZT=S2σT/қ, where S is the Seebeck coefficient, σ is the electrical conductivity, T is the absolute temperature and қ is the thermal conductivity. For practical applications these devices are only cost-effective if the ZT is higher than 2.

The Influence Of Copper Substrate Orientation On Graphene Growth, Zachary Robert Robinson

Legacy Theses & Dissertations (2009 - 2024)

This dissertation is focused on determining the influence of the copper substrate on graphene grown by \ac{CVD}. Graphene, which can be grown in single atomic layers on copper substrates, has potential applications in future electronic devices. One of the key issues for the use of graphene grown by chemical vapor deposition for device applications is the influence of defects on the transport properties of the graphene. For instance, growth on metal foil substrates results in multi-domain graphene growth because the foil substrates themselves have a variety of different surface terminations. Therefore, they don't serve as a very good template for …

Molecular Vapor Deposition Of Organosilanes, Sarah Kirsten Goulet

Legacy Theses & Dissertations (2009 - 2024)

Current strategies for low temperature bonding (<300 C) and 3D integration employ polymer interfaces (1-3 um) with low thermal conductivity which can result in poor heat transfer between bonded elements. The introduction of thinner interfaces to improve heat transfer is desirable; however, deposition of thin polymer films (<100 nm) for bonding applications can lead to reduced film uniformity and negatively affect bonding strength. Self-assembled monolayer (SAM) chemistries provide a potential solution and can yield nanometer control of the interfacial layer thickness without a significant effect on surface roughness. Siloxanes are one available option to realize these nanometer thin reactive layers. Due to their propensity to crosslink and form multilayers, careful control of the reaction conditions is required. Considering this, we have evaluated the molecular vapor deposition of siloxane precursors to generate molecular layers with reactive end-groups for potential use in bonding applications. Film stability, morphology, thickness, and composition were monitored after deposition using atomic force microscopy, ellipsometry and x-ray photoelectron spectroscopy.

A Novel Fabrication Technique For Three-Dimensional Nanostructures, Ravi Kiran Bonam

Legacy Theses & Dissertations (2009 - 2024)

Three dimensional micro- and nano-structures are commonly used in the field of Photonics, Optoelectronics, Sensors and Biological applications. Although numerous physical models are developed, a major challenge has been in their fabrication which is commonly limited to conventional layer-by-layer techniques. In this dissertation, a novel method for fabricating three dimensional structures using Electron Beam Lithography (EBL) will be presented.

The Development And Simulation Of Piezoelectric Surface Acoustic Wave Devices For Euv Mask Particle Removal, Anthony Rae Davis

Legacy Theses & Dissertations (2009 - 2024)

Extreme Ultraviolet Lithography (EUVL) is a critical semiconductor fabrication process which uses 13.5 nanometer wavelength light reflected from a mask to print features on various wafers used for IC fabrication. An extensive amount of research is currently underway to make EUVL prevalent in efforts to allow for efficient sub-22 nm feature size fabrication. A number of challenges must be overcome before EUVL usage becomes feasible in terms of cost, wafer output, reliability, and throughput. One notable challenge in EUVL is the removal of mask contamination. EUV masks are required to be free of contamination to ensure precise feature printing. Particles …

Study Of The Dielectric Function Of Graphene From Spectroscopic Ellipsometry And Electron Energy Loss Spectroscopy, Florence Joan Nelson

Legacy Theses & Dissertations (2009 - 2024)

For more than 60 years, semiconductor research has been advancing up the periodic table. The first transistor was made from germanium. This later gave way to silicon-based devices due to the latter's ability to form an excellent interface with thermally-grown oxide. Now for the last ~8 years, the focus has moved up one more row to carbon for post-CMOS devices in order to comply with the scaling limitations of Moore's law. However, for each of these, the measurements of film properties and dimensions have always been required for technological applications. These measurement methods often incorporate the use of light or …

Materials Engineering For Near-Infrared Light Emission From Silicon Compatible Mos Structures, Himani Suhag Kamineni

Legacy Theses & Dissertations (2009 - 2024)

Silicon-based photonics requires several components, such as a light source, an amplifier/waveguide to transfer the signal, and a photodetector to detect the signal. The motivation for using these silicon-based technologies in photonics applications is two-fold: economic advantages offered by the compatibility with mature silicon IC manufacturing and its excellent material properties for photonic devices (high thermal conductivity, high optical damage threshold, etc.). One of the major challenges in the realization of this technology is the Si-based light source. Because of its indirect bandgap, silicon has very inefficient band-to-band radiative electron-hole recombination. To overcome this obstacle, tremendous research efforts have been …

Graphene Stuctures For Energy Storage Application, Mohammad Arif Ishtiaque Shuvo

Open Access Theses & Dissertations

Energy storage devices are receiving extensive attention in recent years due to the increasing demand of energy. Super-capacitor is one of the energy storage devices with high specific power density and wide applications in electronic vehicles, commercial mobile electronics, and military devices. Carbon based materials are widely used in making Electrochemical Double Layer Capacitor (EDLC) or super-capacitor for their excellent porous nature along with their electron transport capability. By increasing the specific surface area of the porous carbon materials, specific capacitance of the super-capacitor can be significantly improved. Graphene, a newly discovered material, has been incorporated in making super-capacitor electrodes …

Cryogenic Machining And Burnishing Of Az31b Magnesium Alloy For Enhanced Surface Integrity And Functional Performance, Zhengwen Pu

Theses and Dissertations--Mechanical and Aerospace Engineering

Surface integrity of manufactured components has a critical impact on their functional performance. Magnesium alloys are lightweight materials used in the transportation industry and are also emerging as a potential material for biodegradable medical implants. However, the unsatisfactory corrosion performance of Mg alloys limits their application to a great extent. Surface integrity factors, such as grain size, crystallographic orientation and residual stress, have been proved to remarkably influence the functional performance of magnesium alloys, including corrosion resistance, wear resistance and fatigue life.

In this dissertation, the influence of machining conditions, including dry and cryogenic cooling (liquid nitrogen was sprayed to …

Nanocrystals Of Chemotherapeutic Agents For Cancer Theranostics: Development And In Vitro And In Vivo Evaluation, Christin P. Hollis

Theses and Dissertations--Pharmacy

The majority of pharmacologically active chemotherapeutics are poorly water soluble. Solubilization enhancement by the utilization of organic solvents often leads to adverse side effects. Nanoparticle-based cancer therapy, which is passively targeted to the tumor tissue via the enhanced permeation and retention effect, has been vastly developed in recent years. Nanocrystals, which exist as crystalline and carry nearly 100% drug loading, has been explored for delivering antineoplastic agents. Additionally, the hybrid nanocrystal concept offers a novel and simple way to integrate imaging agents into the drug crystals, enabling the achievement of theranostics. The overall objective of this dissertation is to formulate …