High Temperature Wide Bandgap Light Emitting Diodes For Harsh Environment Applications, 2018 University of Arkansas, Fayetteville
High Temperature Wide Bandgap Light Emitting Diodes For Harsh Environment Applications, Stephanie Sandoval
Electrical Engineering Undergraduate Honors Theses
The need for high temperature, high power density power modules for applications such as electric vehicles and space exploration has driven the research into wide bandgap LEDs due to their potential operation at elevated temperatures. Wide bandgap LEDs offer an attractive solution due to properties such as high temperature tolerance, strong radiation hardness and good thermal conductivity. In this thesis, the electrical properties of GaN-on-SiC heterojunctions are studied as a precursor to an LED study, and the optical characterization of an InGaN/GaN MQW is reported. The GaN-on-SiC study revealed that these wide bandgap LEDs have linear sensitivity at high ...
A Novel Design For A Silicon And Cadmium Telluride Tandem Solar Cell., 2018 University of Louisville
A Novel Design For A Silicon And Cadmium Telluride Tandem Solar Cell., Jacob A Vittitow
Electronic Theses and Dissertations
No abstract provided.
Surface Reaction And Diffusion Kinetics In Semiconducting Metal Oxide Film Gas Sensors, 2018 University of Maine
Surface Reaction And Diffusion Kinetics In Semiconducting Metal Oxide Film Gas Sensors, Aravind Reghu
Electronic Theses and Dissertations
Chemiresistive metal oxide gas sensors based on materials such as SnO2, ZnO, and TiO2, have been investigated extensively by many researchers for a wide range of applications. The band bending model, based on the surface chemistry of highly reactive ionosorbed species (O2- or O-) and the semiconducting material properties of SnO2, TiO2 and ZnO, adequately predicts the dependence of the change in sensor conductivity (Δσ) as a function of target gas pressure and temperature. However, the band bending model is not applicable to gas sensors based on reducible oxides such as WO3, MoO3 ...
Increasing The Longevity Of Tungsten Filaments In A Zone Refiner, 2018 Linfield College
Increasing The Longevity Of Tungsten Filaments In A Zone Refiner, Byron D. Greenlee
Zone refining is used for its ability to purify material and grow single crystals. To produce these single crystals, a suspended molten zone, generated by electron bombardment, passes along the polycrystalline stock. During a zone refining run, the filaments that produce the electron bombardment can fail. In this project, the longevity of tungsten filaments in a zone refiner was investigated. A new bombardment geometry was constructed to attempt to increase the longevity of the filaments. The new geometry had a shield machined into it to prevent line-of-sight impurities originating in the molten zone from striking the filaments. It was found ...
Thermoelectrics And Thermoelectric Devices, 2018 Linfield College
Thermoelectrics And Thermoelectric Devices, Benjamin T. Erck
The field of thermoelectrics has many applications, and more are found in everyday systems. From its current studies, it is apparent that improving the figure of merit zT (which defines a good thermoelectric material) is important in the effectiveness of power generation. Another important part of thermoelectrics is the duality of these devices. They can both move heat and generate power, depending on their role in the system. In this thesis research, a process was made to test these thermoelectric relationships for a few Peltier devices in order to understand their efficiencies and what systems they can be applied to.
Design, Fabrication, And Characterization Of Novel Optoelectronic Devices For Near-Infrared Detection, 2018 University of Arkansas, Fayetteville
Design, Fabrication, And Characterization Of Novel Optoelectronic Devices For Near-Infrared Detection, Ahmad Nusir
Theses and Dissertations
Investigating semiconductor materials and devices at the nanoscale has become crucial in order to maintain the exponential development in today’s technology. There is a critical need for making devices lower in power consumption and smaller in size. Nanoscale semiconductor materials provide a powerful platform for optoelectronic device engineers. They own interesting properties which include enhanced photoconductivity and size-tunable interband transitions.
In this research, different types of nanostructures were investigated for optoelectronic devices: nanocrystals, nanowires, and thin-films. First, lead selenide nanocrystals with narrow bandgap were synthesized, size-tailored, and functionalized with molecular ligands for the application of uncooled near-infrared photodetectors. The ...
Glucose Level Estimation Based On Invasive Electrochemical, And Non-Invasive Optical Sensing Methods, 2018 University of Arkansas, Fayetteville
Glucose Level Estimation Based On Invasive Electrochemical, And Non-Invasive Optical Sensing Methods, Sanghamitra Mandal
Theses and Dissertations
The purpose of this research is to design and fabricate sensors for glucose detection using inexpensive approaches. My first research approach is the fabrication of an amperometric electrochemical glucose sensor, by exploiting the optical properties of semiconductors and structural properties of nanostructures, to enhance the sensor sensitivity and response time. Enzymatic electrochemical sensors are fabricated using two different mechanisms: (1) the low-temperature hydrothermal synthesis of zinc oxide nanorods, and (2) the rapid metal-assisted chemical etching of silicon (Si) to synthesize Si nanowires. The concept of gold nano-electrode ensembles is then employed to the sensors in order to boost the current ...
Design, Fabrication, And Characterization Of All-Inorganic Quantum Dot Light Emitting Diodes, 2018 University of Arkansas, Fayetteville
Design, Fabrication, And Characterization Of All-Inorganic Quantum Dot Light Emitting Diodes, Ramesh Vasan
Theses and Dissertations
Quantum dot light emitting diodes are investigated as a replacement to the existing organic light emitting diodes that are commonly used for thin film lighting and display applications. In this, all-inorganic quantum dot light emitting diodes with inorganic quantum dot emissive layer and inorganic charge transport layers are designed, fabricated, and characterized. Inorganic materials are more environmentally stable and can handle higher current densities than organic materials. The device consists of CdSe/ZnS alloyed core/shell quantum dots as the emissive layer and metal oxide charge transport layer. The charge transport in these devices is found to occur through resonant ...
Application Of Modular Multilevel Converters (Mmc) Using Phase-Shifted Pwm And Selective Harmonic Elimination In Distribution Systems, 2018 University of Arkansas, Fayetteville
Application Of Modular Multilevel Converters (Mmc) Using Phase-Shifted Pwm And Selective Harmonic Elimination In Distribution Systems, Thouhidul Islam
Theses and Dissertations
Reducing the size and weight of a power electric system is a prodigious challenge to researchers as the development of the latest technologies emerge in the field of electrical engineering. A similar urge is there to develop a light-weight mobile power substation (MPS) to use in the electric power distribution systems during emergency conditions. This thesis proposes a power electronics based solution using the modular multilevel converter (MMC) topology to design the MPS system. The market-available power semiconductor devices are analyzed and suitable devices are selected to design the system. The phase-shifted pulse width modulation (PS-PWM) and selective harmonic elimination ...
Evaluation Of Terahertz Imaging For Breast Cancer Detection Using Image Morphing, 2018 University of Arkansas, Fayetteville
Evaluation Of Terahertz Imaging For Breast Cancer Detection Using Image Morphing, Tanny Andrea Chavez Esparza
Theses and Dissertations
This thesis proposes the use of a mesh morphing algorithm for the quantitative evaluation of terahertz (THz) images. This work differs from traditional evaluation methods based on qualitative evaluation because it provides a fair and quantitative measurement of the THz imaging system's performance. The objective of the algorithm is to match the alignment, shape, and resolution of the THz and reference pathology images. Therefore, the proposed morphing method provides a pathology reference for a pixel-by-pixel evaluation of the region classification in the THz image. To achieve this, the morphing algorithm aligns the images using the Pearson's correlation coefficient ...
The Eco-Smart Can V2.0, 2018 East Tennessee State University
The Eco-Smart Can V2.0, Darack B. Nanto
Appalachian Student Research Forum
I noticed that the workers had the same itinerary when emptying trashcans, meanwhile trashcans needed urgently to be emptied. Traditionally, ETSU maintenance operate on daily routes to pick trash on designated time, regardless the level of the containers. This leads to overflown trashcan in busy areas or during rush hours in certain areas. This overflown trashcan result in an unclean environment for the community and an unpleasant look of our beautiful campus. The time, resources and labor invested in collecting the trash could be saved. Therefore, I decided to use the Internet of Things (IoT) to create a device that ...
Synthesis, Processing, And Fundamental Phase Formation Study Of Czts Films For Solar Cell Applications, 2018 Florida International University
Synthesis, Processing, And Fundamental Phase Formation Study Of Czts Films For Solar Cell Applications, Osama Awadallah
FIU Electronic Theses and Dissertations
Copper zinc tin sulfide (Cu2ZnSnS4 or CZTS) kesterite compound has attracted much attention in the last years as a new abundant, low cost, and environmentally benign material with desirable optoelectronic properties for Photovoltaic (PV) thin film solar cell applications. Among various synthesis routes for CZTS thin films, sol-gel processing is one of the most attractive routes to obtain CZTS films with superior quality and low cost.
In this study, sol-gel sulfurization process parameters for CZTS thin films were systematically investigated to identify the proper process window. In addition, temperature dependent Raman spectroscopy was employed to monitor the ...
Discharge: Spin-On Anti-Charging Agent For Electron Beam Lithography, 2018 Singh Center for Nanotechnology
Discharge: Spin-On Anti-Charging Agent For Electron Beam Lithography, Gerald G. Lopez Ph.D., Glen De Villafranca
Protocols and Reports
This report documents the chemical DisCharge from DisChem, Inc. used as an anti-charging agent for electron beam lithography at the University of Pennsylvania Singh Center for Nanotechnology Quattrone Nanofabrication Facility. Charge accumulation while exposing atop an electrically insulating substrate can severely impact positional accuracy of the beam yielding poor litho. Using DisCharge has been shown to reduce charge accumulation for insulating substrates such as fused silica pieces, glass slides, and PDMS for positive resists such as PMMA, ZEP520A, CSAR 62 and mr-PosEBR.
Analog Computing Using 1t1r Crossbar Arrays, 2018 University of Massachusetts Amherst
Analog Computing Using 1t1r Crossbar Arrays, Yunning Li
Memristor is a novel passive electronic device and a promising candidate for new generation non-volatile memory and analog computing. Analog computing based on memristors has been explored in this study. Due to the lack of commercial electrical testing instruments for those emerging devices and crossbar arrays, we have designed and built testing circuits to implement analog and parallel computing operations. With the setup developed in this study, we have successfully demonstrated image processing functions utilizing large memristor crossbar arrays. We further designed and experimentally demonstrated the first memristor based field programmable analog array (FPAA), which was successfully configured for audio ...
Crumpling Effects And Specific Absorption Rates Of Flexible Amc Integrated Antennas, 2018 University of North Dakota
Crumpling Effects And Specific Absorption Rates Of Flexible Amc Integrated Antennas, Sima Noghanian, Ala Alemaryeen
Electrical Engineering Faculty Publications
This study presents the design of a wearable textile-based monopole antenna integrated with a flexible artificial magnetic conductor (AMC). The proposed design covers the industrial, scientific, and medical 2.45 GHz band. An AMC reflector is utilised to isolate the human body from undesired electromagnetic radiation and to improve the antenna radiation characteristics. A monopole antenna was backed with an AMC reflector and tested in free space and on human body models. The inclusion of an AMC reflector increases the front-to-back ratio and antenna gain in free space. On the human body models, the AMC antenna provides stable performance and ...
Effect Of Molecular Side Groups And Local Nanoenvironment On Photodegradation And Its Reversibility, 2018 Oregon State University
Effect Of Molecular Side Groups And Local Nanoenvironment On Photodegradation And Its Reversibility, Nicole Quist, Mark Li, Ryan Tollefsen, Michael Haley, John Anthony, Oksana Ostroverkhova
Chemistry Faculty Publications
Degradation of organic semiconductors in the presence of oxygen is one of the bottlenecks preventing their wide-spread use in optoelectronic devices. The first step towards such degradation in functionalized pentacene (Pn) derivatives is formation of endoperoxide (EPO), which can either revert back to the parent molecule or proceed to molecule decomposition. We present the study of reversibility of EPO formation through probing the photophysical properties of functionalized fluorinated pentacene (Pn-R-F8) derivatives. Experiments are done in solutions and in films both at the single molecule level and in the bulk. In solutions, degradation of optical absorption and its partial recovery after ...
Launderability Of Stitched Surface-Mount E-Textiles, 2018 University of Minnesota - Twin Cities
Launderability Of Stitched Surface-Mount E-Textiles, Md. Tahmidul Islam Molla, Crystal Compton, Lucy E. Dunne
International Textile and Apparel Association (ITAA) Annual Conference Proceedings
E-textiles that contain distributed electronic components have advantages for wearable technology in that functionality, particularly for interactive applications that require sensing and actuating, can be spread over a much larger area. Integrating this kind of functionality into a textile architecture also offers advantages for power and networking as well as hand-feel and wearability. However, particularly for garment-based applications, textile-embedded circuitry often must be machine-washable to conform to user expectations for care and maintenance.
In this study, we evaluate the robustness to home laundering of a previously-developed technique for assembling e-textile circuits. We performed a durability test based on machine washing ...
Analog Temperature Control Circuit For A Thin-Film Piezoelectric-On-Substrate Microelectromechanical Systems Oscillator, 2018 University of Central Florida
Analog Temperature Control Circuit For A Thin-Film Piezoelectric-On-Substrate Microelectromechanical Systems Oscillator, Heather Hofstee
Honors Undergraduate Theses
The objective and motivation for this project is to design a low-power, low-noise oven-control circuit to optimize the stability of a MEMS oscillator. MEMS oscillators can be fabricated using conventional semiconductor manufacturing methods and can often be assembled in packages smaller than those of traditional crystal oscillators. However, one of their largest disadvantages currently is their high temperature coefficient of frequency (TCF), causing MEMS oscillators to be especially sensitive to temperature changes. Hence, this project focuses on designing a printed circuit board that will allow the user to manually tune a current passing through a resonator wire-bonded to the board ...
Chip: Clustering Hotspots In Layout Using Integer Programming, 2018 Iowa State University
Chip: Clustering Hotspots In Layout Using Integer Programming, Rohit Reddy Takkala
Clustering algorithms have been explored in recent years to solve hotspot clustering problem in Integrated Circuit design. With various applications in Design for Manufacturability flow such as hotspot library generation, systematic yield optimization and design space exploration, generating good quality clusters along with their representative clips is of utmost importance. With several generic clustering algorithms at our disposal, hotspots can be clustered based on the distance metric defined while satisfying some tolerance conditions. However, the clusters generated from generic clustering algorithms need not achieve optimal results. In this paper, we introduce two optimal integer linear programming formulations based on triangle ...
Parameters Affecting The Resistivity Of Lp-Ebid Deposited Copper Nanowires, 2018 University of Kentucky
Parameters Affecting The Resistivity Of Lp-Ebid Deposited Copper Nanowires, Gabriel Smith
Theses and Dissertations--Electrical and Computer Engineering
Electron Beam Induced Deposition (EBID) is a direct write fabrication process with applications in circuit edit and debug, mask repair, and rapid prototyping. However, it suffers from significant drawbacks, most notably low purity. Work over the last several years has demonstrated that deposition from bulk liquid precursors, rather than organometallic gaseous precursors, results in high purity deposits of low resistivity (LPEBID). In this work, it is shown that the deposits resulting from LP-EBID are only highly conductive when deposited at line doses below 25μC/cm. When the dose exceeds this value, the resulting structure is highly porous providing a poor ...