Nanoscience and Nanotechnology Commons^™

Treated Hfo2 Based Rram Devices With Ru, Tan, Tin As Top Electrode For In-Memory Computing Hardware, Yuvraj Dineshkumar Patel

Theses

The scalability and power efficiency of the conventional CMOS technology is steadily coming to a halt due to increasing problems and challenges in fabrication technology. Many non-volatile memory devices have emerged recently to meet the scaling challenges. Memory devices such as RRAMs or ReRAM (Resistive Random-Access Memory) have proved to be a promising candidate for analog in memory computing applications related to inference and learning in artificial intelligence. A RRAM cell has a MIM (Metal insulator metal) structure that exhibits reversible resistive switching on application of positive or negative voltage. But detailed studies on the power consumption, repeatability and retention …

Novel Electrochemical Sensor Based On Integration Of Nanoporous Gold With Molecularly Imprinted Polymer For Detection Of Arsenic Ion(Iii), Wu-Wei Ma, Qi-Gang Chang, Xiong-Fang Shi, Yan-Bin Tong, Li Zhou, Bang-Ce Ye, Jian-Jiang Lu, Jin-Hu Zhao

Journal of Electrochemistry

Arsenic, a toxic chemical element, is detrimental to environment and human health in particular. Therefore, the development of simple, fast, and accurate arsenic ion (As3+) detection methods has attracted extensive attention. In this work, an electrochemical sensor based on molecular imprinted polymer (MIP) and nano-porous gold (NPG) modified indium tin oxide (ITO) electrode (MIP/NPG/ITO) was developed for determination of As3+ in water with different quality. NPG with high conductivity, large specific surface area and high biocompatibility was prepared in situ on ITO surface by a green electrodeposition method using simple and controllable steps. Then, a layer of MIP was synthesized …

Core-Shell Structured Ru@Ptru Nanoflower Electrocatalysts Toward Alkaline Hydrogen Evolution Reaction, Xue-Liang Wang, Yuan-Yuan Cong, Chen-Xi Qiu, Sheng-Jie Wang, Jia-Qi Qin, Yu-Jiang Song

Journal of Electrochemistry

Water electrolysis for hydrogen production is beneficial for solving the problem of energy crisis and environmental issues. It is necessary to study highly active and cost-effective catalysts toward hydrogen evolution reaction (HER) to reduce the consumption of noble metals. Herein, we report the synthesis of core-shell structured Ru@Pt_0.24Ru nanoflowers electrocatalyst by stepwise reduction of Ru and Pt precursors in the mixture of oleylamine and benzyl alcohol at 160 oC. The average diameter of the resultant Ru@Pt_0.24Ru was 16.5±4.0 nm with a bulk atomic ratio between Pt and Ru of 0.24:1 and a surface ratio of 3.3:1 …

Preparations And Photoelectrochemical Performances Of Rgo-Tio2 Nanotubes Arrays, Ze-Yang Zhang, Lan Sun, Chang-Jian Lin

Journal of Electrochemistry

Decorating TiO₂ nanotube arrays with RGO to improve the photocatalytic activity of TiO₂ nanotube arrays has been reported. For the reported RGO-TiO₂ nanotube arrays, TiO₂ nanotube arrays were prepared by anodizing the high-purity Ti foil in an organic electrolyte for multiple-step treatments, while RGO were deposited on TiO₂ nanotube arrays by using cyclic voltammetry or other electrical reduction methods. To enhance the reduction degree and the coverage of RGO on the resultant RGO-TiO₂ nanotube arrays, in this work, the one-step electrochemical anodization in hydrofluoric acid was used to fabricate TiO₂ nanotube arrays with …

Microparticle Propulsion For In Vivo Navigation, Louis Rogowski

Mechanical Engineering Research Theses and Dissertations

Microscale propulsion impacts a diverse array of fields, with simplistic microrobots allowing for novel innovations in microscale surgery and drug delivery. Propulsion at the microscale is constrained by physics, with time-reversal and geometric symmetries limiting available propulsion mechanisms. However, certain fluid environments and surface coatings allow for the propulsion of microparticles through externally applied magnetic fields. Presented here is a detailed analysis of microparticles propelling using spontaneous symmetry breaking, flagella surface coatings, and multi-modal actuation mechanisms. Spontaneous symmetry breaking in nonlinearly viscoelastic fluids is presented for the first time in literature, with two equal and opposite propulsion states existing along …

Interface Engineering Of Materials For Energy And Biological Applications, Ardalan Chaichi

LSU Doctoral Dissertations

Interface interactions are generally classified into solid-liquid, solid-gas, solid-vacuum, liquid-gas, light-matter and electron-matter categories. Surface morphological studies as well as surface chemical reactions can be studied in various types of complex systems thanks to technological advances in materials characterization methods. By employing interface engineering in different applications, it is possible to control electrical, chemical, mechanical, optical and biological properties of materials. Accordingly, we have applied interface engineering in three different areas of energy materials, biomaterials and surface imaging. As a result, firstly, we have introduced a high intensity light flash-based method on engineered substrates for delamination of reduced graphene oxide …

Probing The Impacts Of Ultra-Low Platinum Loadings On Membrane Degradation Mechanisms, Andre J. Spears

Nanoscience and Microsystems ETDs

Membrane chemical degradation is one of many factors that can impact fuel cell durability. The fuel cell’s performance and lifetime heavily depends on the membrane and its ability to maintain chemical and mechanical integrity. In Nafion^® membranes, hydroxyl radicals are the primary cause of chemical membrane degradation as they attack the membrane’s polymer structure. Radical formation can ensue via peroxide decomposition at the cathode or gases reacting on Pt particles or contaminants like Fe (a fenton's reagent) within the membrane. As radicals attack the membrane’s polymer structure the membrane thins, and fluoride and sulfate ions are released. This consequently …

Fabrication Of Forcespinning® Nanofibers Incorporating Nopal Extract, Cristobal Rodriguez, Victoria Padilla, Karen Lozano, J. Andrew Mcdonald, Luis Materon, Alejandra Chapa, Fariha Ahmad, Carlos Trevino De Leon, Robert Gilkerson

Biology Faculty Publications and Presentations

In this study, nanofibers composed of Opuntia cochenillifera nopal mucilage (N) extract combined with chitosan (CH) and pullulan (PL) (N/CH/PL) were produced via Forcespinning®. The developed nonwoven composite membranes are comprised of long, continuous, and homogenous fibers with fiber average diameter varying between 251±77 nm and 406±127 nm depending on the concentration of N. After crosslinking, the developed membranes were highly stable in water. The water absorption capacity of the N/CH/PL composite nanofiber membranes was shown to be 65% higher when compared to the CH/PL nanofiber membranes. Nopal dipcoated membranes show inhibition of gram-negative Escherichia coli, indicating antibacterial properties. These …

Approaches To Studying Bacterial Biofilms In The Bioeconomy With Nanofabrication Techniques And Engineered Platforms., Michelle Caroline Halsted

Doctoral Dissertations

Studies that estimate more than 90% of bacteria subsist in a biofilm state to survive environmental stressors. These biofilms persist on man-made and natural surfaces, and examples of the rich biofilm diversity extends from the roots of bioenergy crops to electroactive biofilms in bioelectrochemical reactors. Efforts to optimize microbial systems in the bioeconomy will benefit from an improved fundamental understanding of bacterial biofilms. An understanding of these microbial systems shows promise to increase crop yields with precision agriculture (e.g. biosynthetic fertilizer, microbial pesticides, and soil remediation) and increase commodity production yields in bioreactors. Yet conventional laboratory methods investigate these micron-scale …

Optical Properties Of Ultrathin In(Ga)As/Gaas And In(Ga)N/Gan Quantum Wells, Yurii Maidaniuk

Graduate Theses and Dissertations

Recently, structures based on ultrathin quantum wells (QWs) began to play a critical role in modern devices, such as lasers, solar cells, infrared photodetectors, and light-emitting diodes. However, due to the lack of understanding of the formation mechanism of ultrathin QWs during the capping process, scientists and engineers cannot fully explore the potential of such structures. This study aims to investigate how structural parameters of ultrathin QWs affect their emission properties by conducting a systematic analysis of the optical properties of In(Ga)As/GaAs and In(Ga)N/GaN ultrathin QWs. Specifically, the analysis involved photoluminescence measurements combined with effective bandgap simulation, x-ray diffraction, and …

The Varied Thermal Response Of Magnetic Iron-Oxide Nanoparticles During Induction Heating In Liquid And Solid-Liquid Phase Change Mediums, Joshua Tompkins

Graduate Theses and Dissertations

This study investigates the induction heating response of uncapped iron oxide nanoparticles sonically dispersed as a nanofluid and mechanically distributed in solid phase change materials. The nanoparticles examined have a mean diameter of 14.42 nm and are magnetically heated in an alternating magnetic field at an amplitude of 72.6 kA/m at frequencies of 217, 303, and 397 kHz. Nanoparticle characterization was undertaken through transition electron microscopy, x-ray diffraction, and dynamic light scattering when in suspension. Carrier fluids were characterized through viscosity, heat capacity, and density measurements which were used in the calorimetric calculation of the specific absorption rate (SAR) of …

Applications Of Cathodoluminescence In Plasmonic Nanostructures And Ultrathin Inas Quantum Layers, Qigeng Yan

Graduate Theses and Dissertations

Due to the advanced focusing ability, characterization methods based on the electron-beam excitation have been broadly applied to investigate nanomaterials. Structural or compositional information is commonly acquired using electron microscopes. Moreover, taking advantage of the super spatial resolution of the focused electron beam, optical properties of nanomaterials can be also obtained. Herein, general concepts and processes of the interaction between electrons and materials are studied. Two specific optical nanomaterials, including plasmonic nanostructures and semiconductor quantum layers, are investigated by the cathodoluminescence (CL) measurement.

Surface plasmonic resonance can be generated when high-energy electrons strike the interface between the dielectric medium and …

3-D Fabry–Pérot Cavities Sculpted On Fiber Tips Using A Multiphoton Polymerization Process, Jonathan W. Smith, Jeremiah C. Williams, Joseph S. Suelzer, Nicholas G. Usechak, Hengky Chandrahalim

Faculty Publications

This paper presents 3-D Fabry–Pérot (FP) cavities fabricated directly onto cleaved ends of low-loss optical fibers by a two-photon polymerization (2PP) process. This fabrication technique is quick, simple, and inexpensive compared to planar microfabrication processes, which enables rapid prototyping and the ability to adapt to new requirements. These devices also utilize true 3-D design freedom, facilitating the realization of microscale optical elements with challenging geometries. Three different device types were fabricated and evaluated: an unreleased single-cavity device, a released dual-cavity device, and a released hemispherical mirror dual-cavity device. Each iteration improved the quality of the FP cavity's reflection spectrum. The …

Synthesis Of Novel Coo/Mnfe2o4 Heterostructured Nanoparticles And The Effects Of Variable Size And Extent Of Overgrowth On Their Magnetic Properties, Mohammad Tauhidul Islam

MSU Graduate Theses

A combination of thermal decomposition and surfactant-assisted synthesis route was utilized to synthesize novel CoO/MnFe₂O₄ heterostructured nanoparticles. Four samples of varying CoO core size were synthesized with variable extent of overgrowth phase. XRD, XPS, SEM and TEM data show evidence of MnFe₂O₄ spinel phase overgrowth on CoO rock-salt structured nanoparticles. XPS and magnetic data reveal partial oxidation and formation of Co₃O₄ phase on 7 nm and 19 nm size CoO-based nanoparticles. The remaining samples having 22 nm and 34 nm dimensions show a higher percentage of FiM materials overgrowth on the …

Kinetic Monte Carlo Investigations Involving Atomic Layer Deposition Of Metal-Oxide Thinfilms, David Tyler Magness

MSU Graduate Theses

Atomic Layer Deposition is a method of manufacturing thin film materials. Metal-oxides such as zinc-oxide and aluminum-oxide are particularly interesting candidates for use in microelectronic devices such as tunnel junction barriers, transistors, Schottky diodes, and more. By adopting a 3D Kinetic Monte Carlo model capable of simulating ZnO deposition, the effect of parameters including deposition temperature, chamber pressure, and composition of the initial substrate at the beginning of deposition can be investigated. This code generates two random numbers: One is used to select a chemical reaction to occur from a list of all possible reactions and the second is used …

Sustainable Drug Release From Polycaprolactone Coated Chitin‑Lignin Gel Fibrous Scaffolds, Turdimuhammad Abdullah, Kalamegam Gauthaman, Azadeh Mostafavi, Ahmed Alshahrie, Numan Salah, Pierfrancesco Morganti, Angelo Chianese, Ali Tamayol, Adnan Memic

Department of Mechanical and Materials Engineering: Faculty Publications

Non-healing wounds have placed an enormous stress on both patients and healthcare systems worldwide. Severe complications induced by these wounds can lead to limb amputation or even death and urgently require more effective treatments. Electrospun scaffolds have great potential for improving wound healing treatments by providing controlled drug delivery. Previously, we developed fibrous scaffolds from complex carbohydrate polymers [i.e. chitin-lignin (CL) gels]. However, their application was limited by solubility and undesirable burst drug release. Here, a coaxial electrospinning is applied to encapsulate the CL gels with polycaprolactone (PCL). Presence of a PCL shell layer thus provides longer shelf-life for the …

Engineering Electromagnetic Systems For Next-Generation Brain-Machine Interface, Brayan Ricardo Navarrete

FIU Electronic Theses and Dissertations

MagnetoElectric Nanoparticles (MENPs) are known to be a powerful tool for a broad range of applications spanning from medicine to energy-efficient electronics. MENPs allow to couple intrinsic electric fields in the nervous system with externally controlled magnetic fields. This thesis exploited MENPs to achieve contactless brain-machine interface (BMIs). Special electromagnetic devices were engineered for controlling the MENPs’ magnetoelectric effect to enable stimulation and recording. The most important engineering breakthroughs of the study are summarized below.

(I) Metastable Physics to Localize Nanoparticles: One of the main challenges is to localize the nanoparticles at any selected site(s) in the brain. The fundamental …

Editorial: Carbon- And Inorganic-Based Nanostructures For Energy Applications, Federico Cesano, M. Jasim Uddin, Yuanbing Mao, Muhammad N. Huda

Chemistry Faculty Publications and Presentations

No abstract provided.

Radial Basis Densities And The Density Functional-Based Atom-In-Molecule: Designing Charge-Transfer Potentials, Godwin Amo-Kwao

Nanoscience and Microsystems ETDs

Classical potentials that are capable of describing charge transfer and charge polarization in complex systems are of central importance for classical atomistic simulation of biomolecules and materials. Current potentials—regardless of the system—do not generalize well, and, with the exception of highly-specialized empirical potentials tuned for specific systems, cannot describe chemical bond formation and breaking. The charge-transfer embedded atom method (CT-EAM), a formal, DFT-based extension to the original EAM for metals, has been developed to address these issues by modeling charge distortion and charge transfer in interacting systems using pseudoatom building blocks instead of the electron densities of isolated atoms. CT-EAM …

Gan Nanowire Laser For A Universal Atomic Force Microscope Probe: A Computational And Feasibility Study, Neal Wostbrock

Nanoscience and Microsystems ETDs

This thesis attempts to establish the groundwork for integrating a GaN nanowire into an AFM probe resulting in a universal atomic force microscope probe. Previous studies have shown GaN nanowires have stable mechanical properties, can be fabricated at scale with high aspect ratios and very smooth side walls, and have intrinsic lasing capabilities; however, mechanical and lasing capabilities have not yet been integrated into a single AFM probe. Here, we develop and analyze a suspended waveguide optical pumping concept that can be fabricated and applied to an AFM probe cantilever, unlocking full potential of GaN’s optical and mechanical properties as …

Surface Enhanced Raman Spectroscopy (Sers) As A Nanoscale Adsorption Phenomenon: Development Of Tailored Nanomaterials For Applications In Drug Detection, Chiara Deriu

FIU Electronic Theses and Dissertations

Surface Enhanced Raman Spectroscopy (SERS) is an analytical technique in which nanostructured substrates amplify the inherently weak Raman signal of an adsorbed species by several orders of magnitude, enabling the detection of trace compounds, up to the single molecule level. While this may be an exceptional tool for any analytical scientist, SERS is at present relegated to the role of academic sensation, and is underutilized in everyday analytical practice. The SERS community is increasingly attributing this setback to a poor understanding of nanoscale surfaces and their chemical environment; since molecular adsorption at the nanostructured surface enables SERS detection, uncertainty about …

Anisotropic Cuinse2 Nanocrystals: Synthesis, Optical Properties And Their Effect On Photoelectric Response Of Dye-Sensitized Solar Cell, Ahmed Mysara, M Mohsen Abdelaziz, A N. Emam, A S. Mansour, A A. F. Zikry, M .B Mohamed, Y H. Elbashar

Nanotechnology Research Centre

CuInSe₂ I-III-VI₂ ternary is a semiconductor considered very good efficient solar energy conversion material. An organometallic pyrolysis method is used to prepare monodisperse CuInSe₂ nanoparticles using a mixture of oleylamine, and trioctylphosphine, as capping materials. The particle shape changes to dot, rods or flowers occur via varying the reaction temperatures (160, 200, 220±C) respectively. The obtained particles have been characterized to determine the shape and size of CuInSe₂ nanoparticles using HR-TEM and XRD. The optical and electronic properties of these particles have been investigated and discussed in detail. Then the different shapes of CuInSe …

Mitigation Of Electromigration In Metal Interconnects Passivated By Ångstrom-Thin 2d Materials, Yunjo Jeong

USF Tampa Graduate Theses and Dissertations

Electromigration in metal interconnects remains one of the most prominent challenges in the state-of-the-art semiconductor industry. A phenomenon defined as the momentum transfer from electrons in an electric current to the metal atoms in a conductor, electromigration creates voids and hillocks that ultimately cause failures in nanoelectronics due to short or open circuits. Additionally, electromigration induces undesirable diffusion of metal atoms into the dielectric material, forcing the need for a barrier material that can mitigate such adverse effects of the phenomenon. However, extremely tight dimensional control of modern transistor designs imposes reduced dimensions of the interconnects in order to accommodate …

Honokiol Loaded Mpeg-Pcl Micelles For The Treatment Of Age-Related Macular Degeneration, Amna Shahid

USF Tampa Graduate Theses and Dissertations

Age related Macular Degeneration (AMD), a multi-factorial age-related retinal hypoxic disorder resulting in irreversible loss of vision is the foremost cause of blindness in United States. Current treatment strategies used to treat disease involve multiple intraocular injections of Anti – VEGF agents into the vitreous of eye. In addition to the issues of drug localization and targeted delivery, the need to frequently inject drug into the eye raise patient compliance issues. These challenges call for sustained drug delivery system. In this study, a sustained drug delivery system was prepared by loading an anti- HIF agent, honokiol into MPEG-PCL polymer. These …

Modulating Mechanical Properties Of Polymer Composites Via Colloidal Particle Reinforcement, Yusheng Guo

LSU Master's Theses

Additive manufacturing allows the rapid process of complex objects with excellent design flexibility. However, the products often exhibit poor mechanical properties when pure polymer is applied as printable material. In this work, we demonstrate that printability of polymer can be dramatically improved when particle filler is added to form reinforced polymer composites. Furthermore, the interaction between filler and polymer matrix leads to the enhancement in mechanical properties of the printed product. The material reinforcement induced by addition of fillers enables the wide application of polymer composites to print structures with unique features. In the printing of silica-reinforced pNIPAM composite, we …

Electrochemical Engineering Of Carbon Nanodots, Lei Bao, Dai-Wen Pang

Journal of Electrochemistry

Carbon nanodots (CNDs), as zero-dimensional carbonaceous fluorescent nanomaterials, are valuable add-ons to the current cohorts of fluorescent nanoparticles. The fine control over the size and the surface is the key to gain designated photophysical properties of CNDs as well as empowers CNDs in many applications. Herein, a series of electrochemical strategies to manipulate the size and the surface of CNDs and to identify the surface structures was presented. Accordingly, the understandings on the originals of photoluminescence as well as the pathways of electrochemiluminescence of CNDs were revealed. These studies demonstrated that electrochemical methods were easy to operate, cost-effective and efficient …

Cycling Performance And Solid-Electrolyte-Interphase Synergic Formation Of Silicon Nanoparticles In The Concentrated Electrolyte With Additives, Zeng-Hua Chang, Fu-Juan Han, Xi-Xin Yang, Jian-Tao Wang, Shi-Gang Lu

Journal of Electrochemistry

In this paper, the effects of additives on the cycling performance of silicon nanoparticles in LiFSI-(PC)₃ based concentrated electrolytes were systematically studied. The structures of silicon nanoparticle electrodes and the evolution of solid-electrolyte-interphase were characterized by scanning electron microscopy (SEM）, attenuated total reflection Flourier transformed infrared spectroscopy (ATR-FTIR） and X-ray photoelectron spectroscopy (XPS). The results indicated that the additives can efficiently improve the cycling performance of silicon nanoparticle electrodes. In LiFSI-(PC)₃ concentrated electrolyte, the capacity became 574.8 mAh·g-1 after 300 cycles with the initial capacity of 3296.1 mAh·g-1. In contrast, the 3% LiDFOB, 3% FEC and 3% TMSB-containing …

Fundamentals Of Distribution Of Relaxation Times For Electrochemical Impedance Spectroscopy, Jia Wang, Qiu-An Huang, Wei-Heng Li, Juan Wang, Quan-Chao Zhuang, Jiu-Jun Zhang

Journal of Electrochemistry

Electrochemical impedance spectroscopy (EIS) is a powerful electrochemical characterization technology, which has been widely used in the field of electrochemical energy, such as lithium-ion batteries, supercapacitors, fuel cells, etc. Distribution of relaxation time (DRT) is an EIS deconvolution technique which does not depend on the prior knowledge of the targeted research object. Furthermore, DRT can serve to separate and analyze physical and chemical processes which are highly overlapped in their EIS data. In order to encourage the application and popularization of DRT deconvolution technology, several core questions are addressed in this paper: (1) DRT deconvolution principle, implementation steps and important …

Plasmon-Induced Color And Photochemistry, Paul J. Gieri

Nanoscience and Microsystems ETDs

In recent decades, metallic nanostructures have been extensively studied for a variety of applications due to the ability to support surface plasmons. These excitations, which consist of collective resonant oscillations of the conduction electrons, couple strongly to visible light, confining it into subwavelength volumes. In the first part of this work, we study the optical response of metallic nanostructures supported by metallic substrates. We demonstrate that these systems support a charge transfer plasmon mode, whose frequency is primarily determined by the geometry of the contact area between the nanoparticle and the substrate. In the following part, we exploit this knowledge …

Optimal Control Of Active Nematics, Michael M. Norton, Piyush Grover, Michael F. Hagan, Seth Fraden

Department of Mechanical and Materials Engineering: Faculty Publications

In this work we present the first systematic framework to sculpt active nematic systems, using optimal control theory and a hydrodynamic model of active nematics. We demonstrate the use of two different control fields, (i) applied vorticity and (ii) activity strength, to shape the dynamics of an extensile active nematic that is confined to a disk. In the absence of control inputs, the system exhibits two attractors, clockwise and counterclockwise circulating states characterized by two co-rotating topological þ1 2 defects. We specifically seek spatiotemporal inputs that switch the system from one attractor to the other; we also examine phase-shifting perturbations. …