Nanoscience and Nanotechnology Commons^™

Atomistic Simulations Of Novel Nanoscale Semiconductor Devices: Resistance Switches And Two-Dimensional Transistors, Joseph P. Anderson, Mahbubul Islam, David Guzman, Alejandro Strachan

The Summer Undergraduate Research Fellowship (SURF) Symposium

As transistors get smaller, we are achieving record levels of memory density. However, there is a limit to how small transistors can be made before their functionality breaks down. Thus alternatives to traditional transistor technology are needed. The two such technologies we examined are: resistance switching devices, which reversibly grow metal filaments through a dielectric, and two-dimensional transistors, which are capable of breaking through the scalability limit of traditional transistors. In order to design resistance switching devices which create filaments with some level of consistency, the dynamics of the filament formation need to be explored. Herein we model this process …

Modal Phonon Transport Across Interfaces By Non-Equilibrium Molecular Dynamics Simulation, Yang Zhong, Tianli Feng, Xiulin Ruan

The Summer Undergraduate Research Fellowship (SURF) Symposium

Phonons represent the quantization of lattice vibration, responsible for heat transfer in semiconductors and dielectrics. Phonon heat conduction across interfaces is crucially important for the thermal management of real-life devices such as smartphones, electric vehicles, and satellites. Although recent studies have broadly investigated spectral phonon contribution to lattice thermal conductivity, the mechanism of phonon modal transport across interfaces is still not well-understood. Previous models, including the acoustic mismatch model (AMM) and diffuse mismatch model (DMM), only consider elastic process while neglecting inelastic phonon contributions. Herein, we employ spectral Non-Equilibrium Molecular Dynamics Simulation (NEMD) to probe the temperature and heat flux …

Deformation Behavior Of Al/A-Si Core-Shell Nanostructures, Robert Andrew Fleming

Graduate Theses and Dissertations

Al/a-Si core-shell nanostructures (CSNs), consisting of a hemispherical Al core surrounded by a hard shell of a-Si, have been shown to display unusual mechanical behavior in response to compression loading. Most notably, these nanostructures exhibit substantial deformation recovery, even when loaded much beyond the elastic limit. Nanoindentation measurements revealed a unique mechanical response characterized by discontinuous signatures in the load-displacement data. In conjunction with the indentation signatures, nearly complete deformation recovery is observed. This behavior is attributed to dislocation nucleation and annihilation events enabled by the 3-dimensional confinement of the Al core. As the core confinement is reduced, either through …

Fabrication And Characterization Of A Mcro/Nanofluidic Platform For Electroporation., Hanwen Yuan

Electronic Theses and Dissertations

For traditional electroporation devices, there are a number of problems associated with these devices such as insufficient understanding of its theoretical mechanism, low cell viability, inadequate electroporation efficiency, excess voltage applied to generate required electric field due to the large size of these devices and sample contamination. Although newly developed microfluidic electroporation devices have solved most of the above existing problems in traditional bulk electroporation devices, they appear to lack the ability to control the precise dose of biomolecules or genes transfecting into cells and, from a manufacturing perspective, the fabrication methods do not enable repeatable production of such devices …

Magnetic Field-Induced Intramolecular Cyclization As A Trigger For Nanoparticle-Based Delivery Systems., Sara Katherine Biladeau

Electronic Theses and Dissertations

Magnetic nanoparticles (MNPs) are used in a variety of applications, including as agents for magnetic resonance imaging, generation of local hyperthermia, and as platforms for drug delivery. Iron-based MNPs are often coated with a shell, such as silica or gold, to increase biocompatibility for drug delivery applications. Many MNPs used for cancer therapy rely on either an internal trigger, such as a difference in pH, or an external trigger, such as light or an alternating magnetic field (AMF), to cause release of a payload, typically a chemotherapeutic drug. Internal triggers are appealing because drug release can be targeted to a …

Optimal Control-Based Inverse Determination Of Electrode Distribution For Electroosmotic Micromixer, Yuan Li, Yongbo Deng, Zhenyu Liu, Teng Zhou, Yihui Wu, Shizhi Qian

Mechanical & Aerospace Engineering Faculty Publications

This paper presents an optimal control-based inverse method used to determine the distribution of the electrodes for the electroosmotic micromixers with external driven flow from the inlet. Based on the optimal control method, one Dirichlet boundary control problem is constructed to inversely find the optimal distribution of the electrodes on the sidewalls of electroosmotic micromixers and achieve the acceptable mixing performance. After solving the boundary control problem, results are also provided to demonstrate the effectiveness of the proposed method; the step-shaped distribution of the external electric potential imposed on the sidewalls is obtained, and the electrodes with an interlaced arrangement …

Experiment-Based Quantitative Modeling For The Antibacterial Activity Of Silver Nanoparticles, Mohammad Aminul Haque

Graduate Theses and Dissertations

Silver (Ag) has been well known for its antimicrobial activity for a long time. Recent research showed the potential of Ag nanoparticles as emerging antimicrobial agents. However, little quantitative analysis has been performed so far to decipher the mechanism of interaction between nanoparticles and bacteria. Here, a detailed analysis based on kinetic growth assay and colony forming unit assay has been carried out to study the antimicrobial effect of Ag nanoparticles against Escherichia coli (E. coli) bacteria. It was observed that the presence of Ag nanoparticles increased the lag time of bacterial growth while not affecting the maximum growth rate …

Peptide-Directed Nanoparticle Synthesis With A Denovo Pd-Binding Sequence Fused To A Reporter Protein, Rita Eloisa Tejada Vaprio

Graduate Theses and Dissertations

There is a need for low-cost nanoparticle materials in the context of new technologies for catalyst development. The purpose of this work was to recombinantly produce a 45- amino acid long metal binding peptide that is useful for nanoparticle synthesis. Using splicing by overlap extension PCR, a synthetic gene containing the fusion of the metal binding peptide with Green Fluorescent Protein (GFPUV) was constructed. The metal binding peptide, fused to reporter protein GFPUV, was expressed using high cell density fermentation. Palladium nanoparticles of an average diameter of 1.18 0.45 nm were synthesized by using the crude cell extract containing the …

Characterization Of Nanoparticles Using Solid State Nanopores, Santoshi Nandivada

Graduate Theses and Dissertations

Solid state nanopores are widely used in detection of highly charged biomolecules like DNA and proteins. In this study, we use a solid state nanopore based device to characterize spherical nanoparticles to estimate their size and electrical charge using the principle of resistive pulse technique. The principle of resistive pulse technique is the method of counting and sizing particles suspended in a fluid medium, which are electrophoretically driven through a channel and produce current blockage signals due to giving rise to a change in its initial current. This change in current is denoted as a current blockage or as a …

Ion Size Effects On The Properties Of Charge Regulating Electric Double Layers, Divya Jyoti Prakash

Nanoscience and Microsystems ETDs

The behavior of charged interfaces formed in various systems like colloidal solution, fuel cells, battery, electro-deposition, catalysis is governed by the properties of electrical double layer(EDL). Civilized model with charge regulation boundary condition determined by thermodynamic equilibrium at the interface has been used to model electrical double layer and shows that size of the solvent plays a critical role in characterizing the properties of EDL using classical density functional theory.This thesis investigates the impact of ion size in electrolyte solutions on the electrical double layer formed at the interface using a similar model. It is found that ion size greatly …

Copper Electrodeposition In Mesoscale Through-Silicon-Vias, Lyle Alexander Menk

Nanoscience and Microsystems ETDs

Copper (Cu) electrodeposition (ECD) in through-silicon-vias (TSVs) is an essential technique required for high-density 3-D integration of complex semiconductor devices. The importance of Cu ECD in damascene interconnects has led to a natural development towards copper electrodeposition in TSVs. Cu ECD is preferred over alternative approaches like the chemical vapor deposition (CVD) of tungsten (W) or aluminum (Al) because Cu ECD films have lower film stress, lower processing temperatures, and more optimal thermal and electrical properties as compared with CVD W or Al.

Via filling with electroplated Cu on substrates that have undergone atomic layer deposition of a conformal platinum …

Graphite And Graphene-Oxide Based Pgm-Free Model Catalysts For The Oxygen Reduction Reaction, Joseph Henry Dumont

Nanoscience and Microsystems ETDs

The world currently relies heavily on fossil fuels such as coal, oil, and natural gas for its energy. Fossil fuels are non-renewable, that is, they draw on finite resources that will eventually dwindle, becoming too expensive or too environmentally damaging to retrieve. One alternative source of energy are fuel cells, electrochemical devices that convert chemical energy to cleanly and efficiently produce electricity. They can be used in a wide range of applications, including transportation, stationary, portable and emergency power sources. Their development has been slowed by the high cost of PGM electrocatalysts needed at both electrodes as well as sluggish …

Waveguide-Coupled Avalanche Photodiodes For A Cmos Compatible Tranceiver Package, Nick Martinez

Nanoscience and Microsystems ETDs

Optical signal detection is most readily done with classical sources emitting signals

which undergo very little attenuation. Detection of signals with these power levels

benets from classical photodetectors, where the photon induced electronic signal is

discernible above the background noise. In other instances, where the optical signal

may start from an attenuated source, or in cases where the optical signal is severely

attenuated in transit, a detector which exhibits gain converts a weak optical signal

into a measurable electrical one. Detectors which convert a weak photo-generated

electrical pulse into a strong one do so through a process known as carrier …

Role Of Vapor Phase Processes On The Sintering Of Diesel Oxidation Catalysts, Cristhian Carrillo

Nanoscience and Microsystems ETDs

This work provides a fundamental understanding on the vapor phase processes that govern the sintering of supported nanoparticles in relation to the diesel oxidation catalyst (DOC). Sintering is a deactivation process that affects this catalyst significantly, and many other catalyst systems. Therefore, it is important to understand the sintering mechanisms in order to improve the long term catalytic reactivity.

Pt is an active catalyst in the DOC but it sinters via Ostwald ripening to form large particles under the accelerated aging conditions (800 ^oC) recommended by the Department of Energy (DOE). At 800 ^oC in the presence of …

Meniscus-Assisted Solution Printing Of Largegrained Perovskite Films For High-Efficiency Solar Cells, Ming He, Bo Li, Xun Cui, Beibei Jiang, Yanjie He, Yihuang Chen, Daniel O'Neil, Paul Szymanski, Mostafa A. El-Sayed, Jinsong Huang, Zhiqun Lin

Department of Mechanical and Materials Engineering: Faculty Publications

Control over morphology and crystallinity of metal halide perovskite films is of key importance to enable high-performance optoelectronics. However, this remains particularly challenging for solution-printed devices due to the complex crystallization kinetics of semiconductor materials within dynamic flow of inks. Here we report a simple yet effective meniscus-assisted solution printing (MASP) strategy to yield large-grained dense perovskite film with good crystallization and preferred orientation. Intriguingly, the outward convective flow triggered by fast solvent evaporation at the edge of the meniscus ink imparts the transport of perovskite solutes, thus facilitating the growth of micrometre-scale perovskite grains. The growth kinetics of perovskite …

Study Of Polysulfide Speciation In Lithium Sulfur Batteries Using In Situ Confocal Raman Microscopy, Josefine Mcbrayer

Nanoscience and Microsystems ETDs

Secondary lithium sulfur (Li-S) batteries have been heavily studied in the battery community since the start of the 21^st century due to their high theoretical capacity and specific energy density. The ground-breaking lithium ion battery has revolutionized society and its ability to store energy, however the lithium ion battery is reaching its limit with a theoretical capacity almost five times lower than that of lithium sulfur. With the improvement and commercialization of Li-S batteries, electric vehicles and personal electronics will have extended performance on a single charge. The viability of this promising chemistry relies on overcoming several key difficulties, …

Bisphosphonate Functionalized Gold Nanoparticles For The Study And Treatment Of Osteoporotic Disease, Christopher Conners

USF Tampa Graduate Theses and Dissertations

The use of nanoparticles for disease treatment is an increasingly popular area of research. The potential for multi-functionality allows nanoparticles to be used as transport and delivery vehicles for drugs and as diagnostic aides, among other applications, to address the unmet needs of many disease treatments. One such class of disease is osteoporosis including severe disorders, like Paget’s disease, Osteogenesis Imperfecta and Legg Calve Perthes disease. In this dissertation, we discuss a nanoparticle system consisting of gold nanoparticles surface functionalized with primary amine bisphosphonates, which is a classification of pharmaceuticals that is common in the treatment of osteoporosis. Functionalized nanoparticles …

The Efficacy Of Programming Energy Controlled Switching In Resistive Random Access Memory (Rram), David Malien Nminibapiel

Electrical & Computer Engineering Theses & Dissertations

Current state-of-the-art memory technologies such as FLASH, Static Random Access Memory (SRAM) and Dynamic RAM (DRAM) are based on charge storage. The semiconductor industry has relied on cell miniaturization to increase the performance and density of memory technology, while simultaneously decreasing the cost per bit. However, this approach is not sustainable because the charge-storage mechanism is reaching a fundamental scaling limit. Although stack engineering and 3D integration solutions can delay this limit, alternate strategies based on non-charge storage mechanisms for memory have been introduced and are being actively pursued.

Resistive Random Access Memory (RRAM) has emerged as one of the …

Size And Shape Distributions Of Primary Crystallites In Titania Aggregates, Eric A. Grulke, Kazuhiro Yamamoto, Kazuhiro Kumagai, Ines Häusler, Werner Österle, Erik Ortel, Vasile-Dan Hodoroaba, Scott C. Brown, Christopher Chan, Jiwen Zheng, Kenji Yamamoto, Kouji Yashiki, Nam Woong Song, Young Heon Kim, Aleksandr B Stefaniak, D. Schwegler-Berry, Victoria A. Coleman, Åsa K. Jämting, Jan Herrmann, Toru Arakawa, Woodrow W. Burchett, Joshua W. Lambert, Arnold J. Stromberg

Chemical and Materials Engineering Faculty Publications

The primary crystallite size of titania powder relates to its properties in a number of applications. Transmission electron microscopy was used in this interlaboratory comparison (ILC) to measure primary crystallite size and shape distributions for a commercial aggregated titania powder. Data of four size descriptors and two shape descriptors were evaluated across nine laboratories. Data repeatability and reproducibility was evaluated by analysis of variance. One-third of the laboratory pairs had similar size descriptor data, but 83% of the pairs had similar aspect ratio data. Scale descriptor distributions were generally unimodal and were well-described by lognormal reference models. Shape descriptor distributions …

Elastic Properties Of Superconductors And Materials With Weakly Correlated Spins, Christian Binek

Christian Binek Publications

It is shown that in the ergodic regime, the temperature dependence of Young’s modulus is solely determined by the magnetic properties of a material. For the large class of materials with paramagnetic or diamagnetic response, simple functional forms of the temperature derivative of Young’s modulus are derived and compared with experimental data and empirical results. Superconducting materials in the Meissner phase are ideal diamagnets. As such, they display remarkable elastic properties. Constant diamagnetic susceptibility gives rise to a temperature independent elastic modulus for ceramic and single crystalline superconductors alike. The thermodynamic approach established in this report, paves the way to …