Nanotechnology Fabrication Commons^™

Fabrication And Characterization Of Magnetic Nanostructures, Kevin Scott

USF Tampa Graduate Theses and Dissertations

Magnetic permalloy nanostructures were fabricated onto a silicon wafer using electron beam lithography and a liftoff process. The lithography was performed with a Hitachi SU-70 SEM retrofitted with a Nabity NPGS lithography conversion kit. PMMA of 950kDa molecular weight was used as the photoresist. Features were either nanowires, nanodots, or elliptical or rectangular nanostructures. The nanowires had dimensions of 15µm x 200nm x 40nm, the nanodots had diameters of 145nm and thickness of 12nm, and the ellipses and rectangles had dimensions of 110nm x 50nm x 13nm. Characterization of the nanostructures was performed using the same Hitachi SEM as well …

Thermal Characterization Of Liquid Samples With Three-Dimensional On-Chip Micro Calorimeter, Hye Jeong Bak

Master's Theses (2009 -)

This thesis presents a three dimensional on-chip microfabricated calorimeter (μ-calorimeter) to extract thermal diffusivity and specific heat capacity of liquid samples. These thermal properties are used to understand thermal reaction behavior, obtain information of stability for reactant molecules, and characterize a material. Thermally characterized solvents can be utilized to investigate a solute. The μ-calorimeter introduced in this work has 3D wafer-scale structure. The μ-calorimeter consists of a reaction chamber, a nickel heater, and a resistance temperature detector (RTD) sensor. The reaction chamber enables analysis of 200 nl liquid samples. Also, its enclosed structure prevents liquid sample evaporation during an experiment. …

Hybrid Silicon Mode-Locked Laser With Improved Rf Power By Impedance Matching, Bassem M. Tossoun

Master's Theses

The mode-locked laser diode (MLLD) finds a lot of use in applications such as ultra high-speed data processing and sampling, large-capacity optical fiber communications based on optical time-division multiplexing (OTDM) systems. Integrating mode-locked lasers on silicon makes way for highly integrated silicon based photonic communication devices. The mode-locked laser being used in this thesis was built with Hybrid Silicon technology. This technology, developed by UC Santa Barbara in 2006, introduced the idea of wafer bonding a crystalline III- V layer to a Silicon-on-insulator (SOI) substrate, making integrated lasers in silicon chips possible.

Furthermore, all mode-locked lasers produce phase noise, which …

Optical Resonators And Fiber Tapers As Transducers For Detection Of Nanoparticles And Bio-Molecules, Huzeyfe Yilmaz

McKelvey School of Engineering Graduate Student Theses & Dissertations

In recent years, detection of biological interactions on single molecule level has aspired many researchers to investigate several optical, chemical, electrical and mechanical sensing tools. Among these tools, toroidal optical resonators lead the way in detection of the smallest particle/molecule with the real time measurements. In this work, bio-sensing capabilities of toroidal optical resonators are investigated. Bio-sensing is realized via measuring the analyte-antigen interaction while the antigen is immobilized through a novel functionalization method.

Not long ago, detection of single nanoparticles using optical resonators has been accomplished however the need for cost-effective and practical transducers demands simpler tools. A tapered …

Building Predictive Chemistry Models, Christopher Browne, Nicolas Onofrio, Alejandro Strachan

The Summer Undergraduate Research Fellowship (SURF) Symposium

Density Functional Theory (DFT) simulations allow for sophisticated modeling of chemical interactions, but the extreme computational cost makes it inviable for large scale applications. Molecular dynamics models, specifically ReaxFF, can model much larger simulations with greater speed, but with lesser accuracy. The accuracy of ReaxFF can be improved by comparing predictions of both methods and tuning ReaxFF’s parameters. Molecular capabilities of ReaxFF were gauged by simulating copper complexes in water over a 200 ps range, and comparing energy predictions against ReaxFF. To gauge solid state capabilities, volumetric strain was applied to simulated copper bulk and the strain response functions used …

Development Of A Nanomanufacturing Process To Produce Atomically Thin Black Phosphorus, Andrew Stephens, Zhe Luo, Xianfan Xu

The Summer Undergraduate Research Fellowship (SURF) Symposium

Atomically thin black phosphorus (phosphorene) has both unique and desirable properties that differ from bulk black phosphorus. Unlike graphene, phosphorene has a bandgap, which makes it potentially useful for applications in the next generation of transistors. Large-scale applications of phosphorene, like other 2D materials, are limited by current production methods. The most common method of making phosphorene is mechanical exfoliation, which can only produce small and irregular quantities. In this work we investigate a top-down method of producing phosphorene by using a scanning ultrafast laser to thin black phosphorus flakes. Because the bandgap of phosphorene increases as layers are removed, …

Modeling Thermophotovoltaic Rare Earth Based Selective Emitters, Anubha Mathur, Enas Said Sakr, Peter Bermel

The Summer Undergraduate Research Fellowship (SURF) Symposium

Thermophotovoltaic (TPV) devices convert heat to electricity using thermal radiation to illuminate a photovoltaic (PV) diode. Typically, this radiation is generated by a blackbody-like emitter. Such an emission spectrum includes a broad range of wavelengths, but only higher energy photons can be converted by the PV diode, which severely limits efficiencies. Thus, introducing a selective emitter and filter to recycle unwanted photons could potentially greatly enhance performance. In this work, we consider a rare earth-doped selective emitter structure to increase the number of photons emitted above the bandgap of the photovoltaic (PV) cell, while minimizing the total power emitted below …

Nanofabrication Of Metallic Nanostructures And Integration With Light Detection Devices, Liang Huang

Graduate Theses and Dissertations

Metallic nanostructures have been investigated with various applications especially for integration with light detection devices. The incident light can be manipulated by those nanostructures to enhance light absorption therefor improve device performance. However, previous studies focused on optical design. The electrical properties of these integrated light detection devices have not been fully considered. The photon generated carriers transport and collection are critical for light detection devices as well. An optimized device platform considering from both the optical and electrical aspects to fully utilize these nanostructures is highly desired for future light detection devices.

This dissertation targeted on three objectives, beginning …

Optimization Of Plasmon Decay Through Scattering And Hot Electron Transfer, Drew Dejarnette

Graduate Theses and Dissertations

Light incident on metal nanoparticles induce localized surface oscillations of conductive electrons, called plasmons, which is a means to control and manipulate light. Excited plasmons decay as either thermal energy as absorbed phonons or electromagnetic energy as scattered photons. An additional decay pathway for plasmons can exist for gold nanoparticles situated on graphene. Excited plasmons can decay directly to the graphene as through hot electron transfer. This dissertation begins by computational analysis of plasmon resonance energy and bandwidth as a function of particle size, shape, and dielectric environment in addition to diffractive coupled in lattices creating a Fano resonance. With …

Proton Damage Effects On Carbon Nanotube Field-Effect Transistors, Evan R. Kemp

Theses and Dissertations

This research investigated the effects of proton damage on single-walled carbon nanotube (SWCNT) transistors. The transistors were irradiated by 1.8 MeV protons to determine the damage induced in the SWCNTs and the device substrate using Raman spectroscopy, and to observe the effect on transistor functionality by measuring current-voltage characteristics. Irradiation of the SWCNT transistors to a fluence of 1x10¹³ protons/cm² resulted in 67% increase in the Raman D/G peak intensity ratio, while at a fluence of 2x10¹³ protons/cm² the increase in the D/G ratio was only 18%, likely due to radiation annealing. Current-voltage measurements indicated an …

Mos Current Mode Logic (Mcml) Analysis For Quiet Digital Circuitry And Creation Of A Standard Cell Library For Reducing The Development Time Of Mixed Signal Chips, David Marusiak

Master's Theses

Many modern digital systems use forms of CMOS logical implementation due to the straight forward design nature of CMOS logic and minimal device area since CMOS uses fewer transistors than other logic families. To achieve high-performance requirements in mixed-signal chip development and quiet, noiseless circuitry, this thesis provides an alternative toCMOSin the form of MOS Current Mode Logic (MCML). MCML dissipates constant current and does not produce noise during value changing in a circuit CMOS circuits do. CMOS logical networks switch during clock ticks and with every device switching, noise is created on the supply and ground to deal with …

Study Of Grating Layer Location Of A Gan Nano-Grated Led And Comparison Of Triangular And Squared Ito Nano-Grating Of Gan Leds, Ashli Lauren Behill

Electrical Engineering

Reducing energy consumption is one the most critical and necessary actions being continually worked towards by many. According to the U.S. department of Energy, solid-state lighting (SSL) has the potential to reduce the light consumption in the United States by nearly one half and that light-emitting diodes (LEDs) will change the way of lighting in our homes and businesses. Gallium Nitride (GaN) based light emitting diode (LED) technologies are continuing to have a fast growing contribution to various applications in today’s society. GaN LEDS are already replacing the esteemed incandescent light bulb, and are transforming traffic lighting, optical interconnects, backlight …

Clear Circuit Contact Lens, Paul Hecker Ii, Phillip Azar, Alexander Do, Benny Ng, Errol Leon

Electrical Engineering

The clear active contact lens project aims to address safety and hazard awareness with an unexplored field of eye wear technology. With advancements in nanotechnology and the advent of circuits on contact lens, this project is one of the first research and development into this new field, following University of Washington and Google. The team focuses on the safety and biocompatibility of the contact lens for a comfortable ease of use. The designs push the limits of thin film printed technology with its pursuit of fine designs of 250μm antennas. The project streamlines the manufacturing process for a combination substrate …

Fabrication Of Single Nanowire Device Using Electron Beam Lithography, Thach Pham

Graduate Theses and Dissertations

One dimensional nanostructure materials such as nanowires have drawn many interests among the scientific community for a wide range of applications such as field-effect transistors [1], [2], inverters[3], light-emitting diode [1], lasers [4], nanosensors [5], [6], and photodetectors [7]... Comparing with the characterization of nanowire arrays, characterizing a single nanowire will definitely provide a better understanding on new nanowire properties due to simplified behaviors of devices. Although promising theories could be drawn from those results, fabrication of test structure for single nanowire measurements cannot be easily processed using standard microfabrication techniques. Therefore, electron beam lithography integrated with photolithography technique has …

Broadband Nanostructured Antireflection Coating For Enhancing Inas/Gaas Quantum Dots Solar Cells Performance, Jony C. Sarker

Graduate Theses and Dissertations

The broadband suppression in reflection is one of the primary focuses in high efficiency solar cell research. In this thesis, a moth-eye inspired nanostructure antireflection coating is fabricated on InAs/GaAs quantum dots solar cell in order to enhance the power conversion efficiency. The abrupt refractive index transition between air and GaAs surface is replaced by a tapering zinc oxide nanoneedle on planar tantalum pentoxide coating. The antireflection structure provides gradual reduction of refractive index away from the solar cell top surface.

The nanostructured antireflection coating is fabricated by utilizing chemical bath deposition of tapered zinc oxide nanoneedles on planar tantalum …

Nano-Ionic Radiation Sensor: Materials Engineering, Device Design, And Testing, Mahesh Satyanarayana Ailavajhala

Boise State University Theses and Dissertations

For decades, various radiation-detecting materials have been extensively researched, to find a better material or mechanism. Recently, there has been a growing need for smaller, and more effective materials or devices that are Integrated Circuits (IC) compatible, and can perform similar functions as bulkier Geiger counters, and other measurement options, which fail the requirement for easy, cheap, and accurate radiation dose measurements. Here arises the use of thin films of chalcogenide glasses, which have unique properties of high thermal stability along with high sensitivity towards short wavelength radiation.

In this work, the effect of γ-rays, generated from a ⁶⁰Co …

Analytical Parametric Model Used To Study The Influence Of Electrostatic Force On Surface Coverage During Electrospinning Of Polymer Fibers, Joshua Beisel, Jerry Kyeremateng, Lance Purkett, Jessica Andriolo, Jack L. Skinner

Electrical Engineering

Electrospinning (ES) can readily produce polymer fibers with cross-sectional dimensions ranging from tens of nanometers to tens of microns. Qualitative estimates of surface area coverage are rather intuitive. However, quantitative analytical and numerical methods for predicting surface coverage during ES have not been covered in sufficient depth to be applied in the design of novel materials, surfaces, and devices from ES fibers. This article presents a modeling approach to ES surface coverage where an analytical model is derived for use in quantitative prediction of surface coverage of ES fibers. The analytical model is used to predict the diameter of circular …

Modification Of Plasmonic Nano Structures' Absorption And Scattering Under Evanescent Wave Illumination Above Optical Waveguides Or With The Presence Of Different Material Nano Scale Atomic Force Microscope Tips, Gazi Mostafa Huda

Theses and Dissertations--Electrical and Computer Engineering

The interaction of an evanescent wave and plasmonic nanostructures are simulated in Finite Element Method. Specifically, the optical absorption cross section (C_abs) of a silver nanoparticle (AgNP) and a gold nanoparticle (AuNP) in the presence of metallic (gold) and dielectric (silicon) atomic force microscope (AFM) probes are numerically calculated in COMSOL. The system was illuminated by a transverse magnetic polarized, total internally reflected (TIR) waves or propagating surface plasmon (SP) wave. Both material nanoscale probes localize and enhance the field between the apex of the tip and the particle. Based on the absorption cross section equation the author …

Basic Mosfet Fabrication, Daniel A. Ivy

Natural Sciences Student Research Presentations

The MOSFET, or metal-oxide-semiconductor field-effect transistor, are the sole entities responsible for processing in microchips of everyday electronics, yet they have become extremely small. How can one manufacture such a small, powerful product? By using the simple process of pushing ions away with a nearby electric charge, a switch can be compressed down to unimaginable sizes.

Electron – Phonon Interaction In Multiple Channel Gan Based Hfets: Heat Management Optimization, Romualdo A. Ferreyra

Theses and Dissertations

New power applications for managing increasingly higher power levels require that more heat be removed from the power transistor channel. Conventional treatments for heat dissipation do not take into account the conversion of excess electron energy into longitudinal optical (LO) phonons, whose associated heat is stored in the channel unless such LO phonons decay into longitudinal acoustic (LA) phonons via a Ridley path. A two dimensional electron gas (2DEG) density of ~5×10¹²cm^-2 in the channel results in a strong plasmon–LO phonon coupling (resonance) and a minimum LO phonon lifetime is experimentally observed, implying fast heat removal from …

Reference Compensation For Localized Surface-Plasmon Resonance Sensors, Neha Nehru

Theses and Dissertations--Electrical and Computer Engineering

Noble metal nanoparticles supporting localized surface plasmon resonances (LSPR) have been extensively investigated for label free detection of various biological and chemical interactions. When compared to other optical sensing techniques, LSPR sensors offer label-free detection of biomolecular interactions in localized sensing volume solutions. However, these sensors also suffer from a major disadvantage – LSPR sensors remain highly susceptible to interference because they respond to both solution refractive index change and non-specific binding as well as specific binding of the target analyte. These interactions can severely compromise the measurement of the target analyte in a complex unknown media and hence limit …

A Multi-Physics Computational Approach To Simulating Thz Photoconductive Antennas With Comparison To Measured Data And Fabrication Of Samples, Darren Ray Boyd

Theses and Dissertations--Electrical and Computer Engineering

The frequency demands of radiating systems are moving into the terahertz band with potential applications that include sensing, imaging, and extremely broadband communication. One commonly used method for generating and detecting terahertz waves is to excite a voltage-biased photoconductive antenna with an extremely short laser pulse. The pulsed laser generates charge carriers in a photoconductive substrate which are swept onto the metallic antenna traces to produce an electric current that radiates or detects a terahertz band signal. Therefore, analysis of a photoconductive antenna requires simultaneous solutions of both semiconductor physics equations (including drift-diffusion and continuity relations) and Maxwell’s equations. A …

Functionalized Membranes For Environmental Remediation And Selective Separation, Li Xiao

Theses and Dissertations--Chemical and Materials Engineering

Membrane process including microfiltration (MF), ultrafiltration (UF), nanofiltration (NF) and reverse osmosis (RO) have provided numerous successful applications ranging from drinking water purification, wastewater treatment, to material recovery. The addition of functional moiety in the membranes pores allows such membranes to be used in challenging areas including tunable separations, toxic metal capture, and catalysis. In this work, polyvinylidene fluoride (PVDF) MF membrane was functionalized with temperature responsive (poly(N-isopropylacrylamide), PNIPAAm) and pH responsive (polyacrylic acid, PAA) polymers. It’s revealed that the permeation of various molecules (water, salt and dextran) through the membrane can be thermally or pH controlled. The introduction of …

Investigation Of The Effects Of Rapid Thermal Annealing On Mbe Grown Gaasbi/Gaas Heterostructures For Optoelectronic Devices, Perry C. Grant

Graduate Theses and Dissertations

High efficiency optoelectronic devices rely on high quality materials making up the device structure. The scope of this thesis investigates the effectiveness of rapid thermal annealing (RTA) at improving the material quality of GaAsBi/GaAs heterostructures. During the fabrication of a device, the contacts of the device had the rapid thermal annealing process accomplished to produce ohmic contacts and this research explored if this annealing treatment degraded the quantum wells that made up the active region of a device. To investigate these effects, a system to measure the photoluminescence of the material system was constructed utilizing Fourier Transform Infrared Spectroscopy. The …

Monodentate, Bidentate And Photocrosslinkable Thiol Ligands For Improving Aqueous Biocompatible Quantum Dots, Hiroko Takeuchi

Graduate Theses and Dissertations

Water-soluble Quantum Dots (QDs) are highly sensitive fluorescent probes that are often used to study biological species. One of the most common ways to render QDs water-soluble for such applications is to apply hydrophilic thiolated ligands to the QD surface. However, these ligands are labile and can be easily exchanged on the QD surface, which can severely limit their application. As one way to overcome this limitation while maintaining a small colloidal size of QDs, we developed a method to stabilize hydrophilic thiolated ligands on the surface of QDs through the formation of a crosslinked shell using a photocrosslinking approach. …

Finite-Difference Time-Domain Simulation Of Photovoltaic Structures Using A Graphical User Interface For Meep, Xin Tze Tee, Peter Bermel

The Summer Undergraduate Research Fellowship (SURF) Symposium

There is a large and growing need for accurate full-wave optical simulations of complex systems such as photovoltaic (PV) cells, particularly at the nanoscale. A finite-difference time-domain tool known as MEEP offers this capability in principle, through C++ libraries and the Scheme programming language. For expert users, this approach has been quite successful, but there is also great interest from new and less frequent users in starting to use MEEP. In order to facilitate this process, we have developed a graphical user interface (GUI) for MEEP, geared toward simulation of 2D and 3D PV cell geometries, freely available through a …

Mems Lab Simulation Tool, Oluwatosin D. Adeosun, Sambit Palit, Ankit Jain, Muhammad A. Alam

The Summer Undergraduate Research Fellowship (SURF) Symposium

MEMS actuators have multiple design applications. Understanding their behavior as well as the ability to predict their actuation characteristics and voltage response is important when designing these actuators. In order to know these devices will behave, designers have to solve multiple analytical equations and experiments that can be very time consuming. Over the course of the summer a tool was created on nanoHUB that will allow users to enter information about a MEMS actuator and provide the voltage response of the actuator. To create the tool, scaling equations were first provided for various geometry configurations and the equations were next …

Stanford Stratified Structure Solver (S4) Simulation Tool, Chang Liu, Xufeng Wang, Peter Bermel

The Summer Undergraduate Research Fellowship (SURF) Symposium

The Stanford Stratified Structure Solver (S4) developed in 2012 allows for fast, accurate prediction of optical propagation through complex 3D structures. However, there have been two key challenges preventing wider use to date: the use of a specialized control language, and the difficulty of incorporating realistic materials parameters. In this project, both concerns have been addressed. We have constructed a graphical user interface as an alternative, using the open-source Rappture platform on nanoHUB. This has been combined with a comprehensive materials database known as PhotonicsDB, which incorporates materials optical data drawn from carefully vetted sources. An Octave script file was …

Thermophotovoltaic System Efficiency Simulation, Qingshuang Chen, Roman Shugayev, Peter Bermel

The Summer Undergraduate Research Fellowship (SURF) Symposium

Thermophotovoltaic (TPV) power systems, which convert heat into electricity using a photovoltaic diode to collect thermal radiation, have attracted increasing attention in recent work. It has recently been proposed that new optical structures such as photonic crystals can significantly improve the efficiency of these devices in two ways. First, the electronic bandgap of the TPV diode should match the photonic bandgap of the emitter, in order to ensure that the majority of emitted photons can be converted. Second, a photonic crystal short-pass optical filter can be added to the front of the TPV diode to send long wavelength photons back …

Metal-Assisted Etching Of Silicon Molds For Electroforming, Ralu Divan, Dan Rosenthal '14, Karim Ogando, Leonidas E. Ocola, Daniel Rosenmann, Nicolaie Moldovan

Student Publications & Research

Ordered arrays of high-aspect-ratio micro/nanostructures in semiconductors stirred a huge scientific interest due to their unique one-dimensional physical morphology and the associated electrical, mechanical, chemical, optoelectronic, and thermal properties. Metal-assisted chemical etching enables fabrication of such high aspect ratio Si nanostructures with controlled diameter, shape, length, and packing density, but suffers from structure deformation and shape inconsistency due to uncontrolled migration of noble metal structures during etching. Hereby the authors prove that a Ti adhesion layer helps in stabilizing gold structures, preventing their migration on the wafer surface while not impeding the etching. Based on this finding, the authors demonstrate …