Engineering Commons^™

Iii-Nitride Nanostructures: Photonics And Memory Device Applications, Barsha Jain

Dissertations

III-nitride materials are extensively studied for various applications. Particularly, III-nitride-based light-emitting diodes (LEDs) have become the major component of the current solid-state lighting (SSL) technology. Current III-nitride-based phosphor-free white color LEDs (White LEDs) require an electron blocking layer (EBL) between the device active region and p-GaN to control the electron overflow from the active region, which has been identified as one of the primary reasons to adversely affect the hole injection process. In this dissertation, the effect of electronically coupled quantum well (QW) is investigated to reduce electron overflow in the InGaN/GaN dot-in-a-wire phosphor-free white LEDs and to improve the …

Integration Of Blockchain Technology Into Automobiles To Prevent And Study The Causes Of Accidents, John Kim

Electronic Theses, Projects, and Dissertations

Automobile collisions occur daily. We now live in an information-driven world, one where technology is quickly evolving. Blockchain technology can change the automotive industry, the safety of the motoring public and its surrounding environment by incorporating this vast array of information. It can place safety and efficiency at the forefront to pedestrians, public establishments, and provide public agencies with pertinent information securely and efficiently. Other industries where Blockchain technology has been effective in are as follows: supply chain management, logistics, and banking. This paper reviews some statistical information regarding automobile collisions, Blockchain technology, Smart Contracts, Smart Cities; assesses the feasibility …

A Double-Sided Stack Low-Inductance Wire-Bondless Sic Power Module With A Ceramic Interposer, Si Huang

Graduate Theses and Dissertations

The objective of this dissertation research is to develop a novel three-dimensional (3-D) wire bondless power module package for silicon carbide (SiC) power devices to achieve a low parasitic inductance and an improved thermal performance. A half-bridge module consisting of 900-V SiC MOSFETs is realized to minimize stray parasitic inductance as well as to provide both vertical and horizontal cooling paths to maximize heat dissipation. The proposed 3-D power module package was designed, simulated, fabricated and tested. In this module, low temperature co-fired ceramic (LTCC) substrate with vias is utilized as an interposer of which both top and bottom sides …

Investigation Of Optical And Structural Properties Of Gesn Heterostructures, Oluwatobi Gabriel Olorunsola

Graduate Theses and Dissertations

Silicon (Si)-based optoelectronics have gained traction due to its primed versatility at developing light-based technologies. Si, however, features indirect bandgap characteristics and suffers relegated optical properties compared to its III-V counterparts. III-Vs have also been hybridized to Si platforms but the resulting technologies are expensive and incompatible with standard complementary-metal-oxide-semiconductor processes. Germanium (Ge), on the other hand, have been engineered to behave like direct bandgap material through tensile strain interventions but are well short of attaining extensive wavelength coverage. To create a competitive material that evades these challenges, transitional amounts of Sn can be incorporated into Ge matrix to form …

Additive Manufacturing Using Robotic Manipulators, Fdm, And Aerosol Jet Printers., Alexander Curry

Electronic Theses and Dissertations

Additive manufacturing has created countless new opportunities for fabrication of devices in the past few years. Advances in additive manufacturing continue to change the way that many devices are fabricated by simplifying processes and often lowering cost. Fused deposition modeling (FDM) is the most common form of 3D printing. It is a well-developed process that can print various plastic materials into three-dimensional structures. This technology is used in a lot of industries for rapid prototyping and sometimes small batch manufacturing. It is very inexpensive, and a prototype can be created in a few hours, rather than days. This is useful …

Modeling And Characterization Of Optical Metasurfaces, Mahsa Torfeh

Masters Theses

Metasurfaces are arrays of subwavelength meta-atoms that shape waves in a compact and planar form factor. During recent years, metasurfaces have gained a lot of attention due to their compact form factor, easy integration with other devices, multi functionality and straightforward fabrication using conventional CMOS techniques. To provide and evaluate an efficient metasurface, an optimized design, high resolution fabrication and accurate measurement is required. Analysis and design of metasurfaces require accurate methods for modeling their interactions with waves. Conventional modeling techniques assume that metasurfaces are locally periodic structures excited by plane waves, restricting their applicability to gradually varying metasurfaces that …

Towards Higher Power Factor In Semiconductor Thermoelectrics: Bandstructure Engineering And Potential Barriers, Adithya Kommini

Doctoral Dissertations

To keep up with the current energy demand and to sustain the growth requires efficient use of existing resources. One of the ways to improve efficiency is by converting waste heat to electricity using thermoelectrics. Thermoelectric devices work on the principle of Seebeck effect, where an applied temperature difference across the material results in a potential difference in the material. The possibility of drastic improvements in the efficiency of thermoelectric (TE) devices using semiconductor nanostructured materials renewed interest in thermoelectrics over the last three decades. Introducing confinement, interfaces, and quantum effects using nanostructures for additional control of charge and phonon …

On Improving Robustness Of Hardware Security Primitives And Resistance To Reverse Engineering Attacks, Vinay C. Patil

Doctoral Dissertations

The continued growth of information technology (IT) industry and proliferation of interconnected devices has aggravated the problem of ensuring security and necessitated the need for novel, robust solutions. Physically unclonable functions (PUFs) have emerged as promising secure hardware primitives that can utilize the disorder introduced during manufacturing process to generate unique keys. They can be utilized as \textit{lightweight} roots-of-trust for use in authentication and key generation systems. Unlike insecure non-volatile memory (NVM) based key storage systems, PUFs provide an advantage -- no party, including the manufacturer, should be able to replicate the physical disorder and thus, effectively clone the PUF. …

Metasurface Design And Optimization With Adjoint Method, Mahdad Mansouree

Doctoral Dissertations

The invention and advancement of optical devices have tremendously changed our life. Devices such as cameras, displays and optical sensors are now an integral part of our lives. Moreover, with the rapid growth in new markets such as virtual reality (VR), augmented reality (AR), autonomous vehicles and internet of things (IoT) the need for optical devices is expected to grow considerably. Recent advances in nano-fabrication techniques have spurred a new wave of interest in optical metasurfaces. Metasurfaces are arrays of wisely selected nano-scattereres that generate desired transformation on the incident light. Metasurfaces provide a new platform for the development of …

Development Of A Point-Of-Use Testing Platform For Detecting Bacteria Infection In Raw Milk, Xin Xia

Masters Theses

The detection and quantification of bacteria are essential to environment and food quality monitoring. Escherichia coli (E. coli) is a common pathogen, also a causative agent of mastitis. Traditional methods usually require samples to be tested in a laboratory. However, sending samples to remote lab increases the cost of time and money spent on delivery. Sometimes, samples can degrade during this long progress and cause inaccuracy. A low cost and reusable sensor is designed to perform on-site quantification. The sensor composed of two layers of asymmetrical mesh electrodes, which is used in coordination magnetic microparticles functionalized with bacterium-specific antibody. Immunological …

Development Of A Wireless Telemetry Load And Displacement Sensor For Orthopaedic Applications, William Anderson

Electronic Thesis and Dissertation Repository

Due to sensor size and supporting circuitry, in vivo load and deformation measurements are currently restricted to applications within larger orthopaedic implants. The objective of this thesis is to repurpose a commercially available low-power, miniature, wireless, telemetric, tire-pressure sensor (FXTH87) to measure load and deformation for future use in biomechanical applications. The capacitive transducer membrane of the FXTH87 was modified, and a relationship was reported between applied compressive deformation and sensor signal value. The sensor package was embedded within a deformable enclosure to illustrate potential applications of the sensor for monitoring load. Finite element analysis was an effective tool to …

Thermoelectric Transport In Disordered Organic And Inorganic Semiconductors, Meenakshi Upadhyaya

Doctoral Dissertations

The need for alternative energy sources has led to extensive research on optimizing the conversion efficiency of thermoelectric (TE) materials. TE efficiency is governed by figure-of-merit (ZT) and it has been an enormously challenging task to increase ZT > 1 despite decades of research due to the interdependence of material properties. Most doped inorganic semiconductors have a high electrical conductivity and moderate Seebeck coefficient, but ZT is still limited by their high lattice thermal conductivity. One approach to address this problem is to decrease thermal conductivity by means of alloying and nanostructuring, another is to consider materials with an inherently low …

Distributed Modeling Approach For Electrical And Thermal Analysis Of High-Frequency Transistors, Amirreza Ghadimi Avval

Graduate Theses and Dissertations

The research conducted in this dissertation is focused on developing modeling approaches for analyzing high-frequency transistors and present solutions for optimizing the device output power and gain. First, a literature review of different transistor types utilized in high-frequency regions is conducted and gallium nitride high electron mobility transistor is identified as the promising device for these bands. Different structural configurations and operating modes of these transistors are explained, and their applications are discussed. Equivalent circuit models and physics-based models are also introduced and their limitations for analyzing the small-signal and large-signal behavior of these devices are explained. Next, a model …

Design And Validation Of A High-Power, High Density All Silicon Carbide Three-Level Inverter, Zhongjing Wang

Graduate Theses and Dissertations

Transportation electrification is clearly the road toward the future. Compared to internal combustion engine, the electrified vehicle has less carbon-dioxide emission, less maintenance costs and less operation costs. It also offers higher efficiency and safety margin. More importantly, it relieves human’s dependence on conventional fossil energy. In the electrification progress, the revolution of electric traction drive systems is one of the most important milestone. The traction system should keep high efficiency to avoid performance reduction. Moreover, the motor drive should be designed within limited space without sacrificing output power rating. Based on the road map from US Drive Electrical and …

Direct Torque Control For Silicon Carbide Motor Drives, Mohammad Hazzaz Mahmud

Graduate Theses and Dissertations

Direct torque control (DTC) is an extensively used control method for motor drives due to its unique advantages, e.g., the fast dynamic response and the robustness against motor parameters variations, uncertainties, and external disturbances. Using higher switching frequency is generally required by DTC to reduce the torque ripples and decrease stator current total harmonic distortion (THD), which however can lower the drive efficiency. Through the use of the emerging silicon carbide (SiC) devices, which have lower switching losses compared to their silicon counterparts, it is feasible to achieve high efficiency and low torque ripple simultaneously for DTC drives.

To overcome …

Use Of The Igbt Module In The Active Region To Design A High Current Active Filter, Jorge F. Galarraga

Graduate Theses and Dissertations

Particle accelerators require high-precision magnetic fields on the order or 100ppm or less. This implies that the precision of the associated electrical current in the electromagnet that generates these fields should be smaller than 100ppm. However, conventional switching power supplies cannot offer this precision due to the frequency limitation of the switches. This research considers the use of power electronics devices operating in a linear as an alternative solution to meet the requirements of particle accelerator electromagnets.

This thesis presents the study of an insulated-gate bipolar transistor (IGBT) driver using a new control method that linearizes the IGBT’s collector-emitter voltage …

Electro-Thermal Transport In Two-Dimensional Materials And Their Heterostructures, Arnab K. Majee

Doctoral Dissertations

”Smaller is better” is the mantra that has driven semiconductor industry for the past 50 years. The on-going quest for faster electronic switching, higher transistor density, and better device performance, has been driven by a self-fulfilling prophecy popularly known as Moore’s law, according to which the number of transistors per unit area of a chip doubles itself approximately every two years. A modern smartphone has about 8 billion transistors, which is as large as current earth’s population. Although each transistor dissipates negligible power, but the collective power dissipation from all the transistors in an electronic gadget and inefficient heat removing …

On-Chip Nanoscale Plasmonic Optical Modulators, Abdalrahman Mohamed Nader Abdelhamid

Theses and Dissertations

In this thesis work, techniques for downsizing Optical modulators to nanoscale for the purpose of utilization in on chip communication and sensing applications are explored. Nanoscale optical interconnects can solve the electronics speed limiting transmission lines, in addition to decrease the electronic chips heat dissipation. A major obstacle in the path of achieving this goal is to build optical modulators, which transforms data from the electrical form to the optical form, in a size comparable to the size of the electronics components, while also having low insertion loss, high extinction ratio and bandwidth. Also, lap-on-chip applications used for fast diagnostics, …

Design And Characterization Of Standard Cell Library Using Finfets, Phanindra Datta Sadhu

Master's Theses

The processors and digital circuits designed today contain billions of transistors on a small piece of silicon. As devices are becoming smaller, slimmer, faster, and more efficient, the transistors also have to keep up with the demands and needs of the daily user. Unfortunately, the CMOS technology has reached its limit and cannot be used to scale down due to the transistor's breakdown caused by short channel effects. An alternative solution to this is the FinFET transistor technology, where the gate of the transistor is a three dimensional fin that surrounds the transistor and prevents the breakdown caused by scaling …

Fault Modeling And Test Vector Generation For Asic Devices Exposed To Space Single Event Environment, Ahmed Mohamed

Theses and Dissertations

This work aims at providing a concise automated flow to predict the effect of Single Event Transients (SETs) on ASIC chips by developing a method to characterize the circuit susceptibility to SET pulses propagation and then generation of the required input vectors that sensitize the victim paths. A new enhanced method for SET electrical propagation modeling is proposed and compared to a previously published analytical model. The method was applied on different standard cells libraries built over XFAB Xh018 technology and verified for accuracy against simulations. The new method showed enhancement in accuracy compared with previous work in literature. Industrial …

Low-Energy Memristors & High-Nonlinearity Selector For Dense Passive Cross-Bar Arrays, Navnidhi K. Upadhyay

Doctoral Dissertations

Memristor or RRAM (Resistive Random Access Memory) based crossbar array architecture (CBA) is considered a leading contender for the next-generation non-volatile memory (NVM) as well as for future computing paradigms, such as in-memory computing, neuromorphic computing, neural networks, analog computing, reconfigurable computing, etc. Among many other attractive properties, memristors’ simple and dense 3D stackable structure is an essential enabler of these promising applications. However, the simplicity and high density of CBA comes at a price. CBA suffers from the so-called sneak path currents flowing through the unselected cells, which severely affects the read margin, makes CBA more power-hungry, increases the …

Autonomous Mortar Remote Control Center, James Tyler Frame

Honors Capstone Projects and Theses

No abstract provided.

Malicious Hardware & Its Effects On Industry, Gustavo Perez

Computer Science and Computer Engineering Undergraduate Honors Theses

In recent years advancements have been made in computer hardware security to circumnavigate the threat of malicious hardware. Threats come in several forms during the development and overall life cycle of computer hardware and I aim to highlight those key points. I will illustrate the various ways in which attackers exploit flaws in a chip design, or how malicious parties take advantage of the many steps required to design and fabricate hardware. Due to these exploits, the industry and consumers have suffered damages in the form of financial loss, physical harm, breaches of personal data, and a multitude of other …

Transimpedance Amplification Of Optocoupler Output For High Temperature Applications, Kara Maurer

Electrical Engineering Undergraduate Honors Theses

When looking to the future of electronics, one characteristic is becoming more lucrative: high temperature capabilities. With the goals of not only becoming more efficient electronically, spatially, and cost-wise, adapting electronics for a high temperature environment can potentially be a route to all three of these goals. Not only does it take away the need for a cooling method, but it can also increase the longevity of a product which can make it even more cost effective. In an effort to contribute to the push for high temperature electronics, the University of Arkansas is developing a high temperature power module …

Si-Based Germanium Tin Photodetectors For Infrared Imaging And High-Speed Detection, Huong Tran

Graduate Theses and Dissertations

Infrared (IR) radiation spans the wavelengths of the windows: (1) near-IR region ranging from 0.8 to 1.0 μm, (2) shortwave IR (SWIR) ranging from 1.0 to 3.0 μm, (3) mid-wave IR (MWIR) region covering from 3.0 to 5.0 μm, (4) longwave IR (LWIR) spanning from 8.0 to 12.0 μm, and (5) very longwave IR extending beyond 12.0 μm. The MWIR and LWIR regions are important for night vision in the military, and since the atmosphere does not absorb at these wavelengths, they are also used for free-space communications and astronomy. Automotive and defect detection in the food industry and electronic …

An Accurate And Efficient Electro-Thermal Compact Model Of Sic Power Mosfet Including Third Quadrant Behavior, Arman Ur Rashid

Graduate Theses and Dissertations

Due to narrower bandgap and lower critical electric field, silicon (Si) power devices have reached their limit in terms of the maximum blocking voltage capability. Exploiting this limitation, wide bandgap devices, namely silicon carbide (SiC) and gallium nitride (GaN) devices, are increasingly encroaching on the lucrative power electronics market. Unlike GaN, SiC devices can exploit most of the established fabrication techniques of Si power devices. Having substrate of the same material, vertical device structures with higher breakdown capabilities are feasible in SiC, unlike their GaN counterpart. Also, the excellent thermal conductivity of SiC, compared to GaN and Si, let SiC …

Optoelectronic Valley-Spin Qubits With Ambipolar Quantum Dots, Jeremy Tull

Electrical Engineering Undergraduate Honors Theses

The current limitations of qubit-based processors are caused by imperfections in quantum gates, leading to a lack of gate fidelity. Gate fidelity can be refined by extending the coherence of qubits and reducing logic operation speed. A potential solution is to develop a hybrid qubit that has the coherence of electrically-controlled quantum dots and the gate speed of their optically-controlled counterparts. Quantum bits that utilize ultrafast optical gating to perform gate operations require precise control of the gating pulse duration. Optical dispersion can cause adverse effects pulse duration, such as pulse broadening, so dispersion-compensation techniques must be employed; by properly …

Design And Fabrication Of A Microstrip Bandpass Filter In Ltcc, Allison Rucker

Electrical Engineering Undergraduate Honors Theses

The goal of the project was to design and fabricate a bandpass filter with a center frequency of 25GHz with a 2GHz bandwidth. The first step was to do the calculation to design a bandpass filter to meet these specifications along with the properties of the Dupont^TM GreenTape^TM 9K7. HFSS was then used to verify the results from the initial calculations. There was a significant error between the two results, so more tweaking was done to the calculations to get a better center frequency. After a final design was decided, the fabrication process started. Low-Temperature Co-Fired Ceramics (LLTC) …

Performance And Economics Of Solar Inverters And Module Level Power Electronics In A 1 Mw Photovoltaic System, Maxwell Criswell

Biological and Agricultural Engineering Undergraduate Honors Theses

Photovoltaic solar panels convert sunlight to electricity in the form of direct current; therefore, a necessary component of every photovoltaic system is an inverter to convert the electricity to usable alternating current. There are various commercially available inverter technologies manufactured today such as microinverters, string inverters, and central inverters, as well as module level power electronic devices such as DC optimizers that are capable of improving system performance in string and central inverter systems. This thesis compares the performance and economics of five different inverter and module level power electronic systems through model simulation using Helioscope software. The five alternatives …

Effect Of Silicon Carbide On Electric Drivetrains Of Heavy-Duty Vehicles, Haley Solera

Electrical Engineering Undergraduate Honors Theses

The application of electro-mechanical motors in rigorous, high-temperature systems is constantly adapting to suit the growing needs of developers in the automotive, construction, and aerospace industries. With improved efficiency, torque, and environmental impact over conventional internal combustion engines, electric drive trains pose more than ample incentive for manufacturers to invest considerable resources toward the design of newer, better methods of electric propulsion. This paper discusses the motives behind the electrification of heavy-duty vehicles, the state-of-the-art technology currently available on the market, and the novel application of silicon carbide to electric drive trains as a means of increasing their heat tolerance, …